A Mathematical-Model of the Solid-Polymer-Electrolyte Fuel-Cell
Bernardi, DM; Verbrugge, MW
Two-phase flow and transport in the air cathode of proton exchange membrane fuel cells
Wang, ZH; Wang, CY; Chen, KS
A Water and Heat Management Model for Proton-Exchange-Membrane Fuel-Cells
Nguyen, TV; White, RE
Two-dimensional model for proton exchange membrane fuel cells
Gurau, V; Liu, HT; Kakac, S
燃料電池技術(shù)發(fā)展現(xiàn)狀與展望*
侯明,衣寶廉
(中國科學(xué)院大連化學(xué)物理研究所,遼寧大連116023)
燃料電池現(xiàn)狀與未來
衣寶廉
燃料電池
·編者按·
能源是社會(huì)發(fā)展和科技進(jìn)步的重要物質(zhì)基礎(chǔ),是國民經(jīng)濟(jì)發(fā)展的動(dòng)力,也是衡量一國綜合國力、國家文明發(fā)達(dá)程度和人民生活水平的重要指標(biāo).目前我們所用的能源仍然是以化石燃料為主的傳統(tǒng)能源,這些傳統(tǒng)能源的能量轉(zhuǎn)化率低、污染嚴(yán)重、儲(chǔ)量有限且不可再生.燃料電池(Fuel Cell,F(xiàn)C)技術(shù)清潔、高效、無污染,被視為21世紀(jì)最具發(fā)展?jié)摿Φ那鍧嵞茉醇夹g(shù),也是近年來各國爭相占領(lǐng)的新能源技術(shù)制高點(diǎn)之一.
1839年,英國科學(xué)家格羅夫(W. R. Grove)首次提出了燃料電池技術(shù),20世紀(jì)60年代美國國家航空航天局(NASA)率先開始燃料電池技術(shù)和產(chǎn)業(yè)化的研究,并將其作為輔助電源應(yīng)用到Gemini航天領(lǐng)域,為探測器、人造衛(wèi)星和太空艙提供電力.從此以后,該技術(shù)引起了世界各國政府、科研機(jī)構(gòu)和企業(yè)的高度重視,就開始被廣泛使用在工業(yè)、住屋、交通等方面,作為基本或后備供電裝置,逐步走向了實(shí)用化.燃料電池是把燃料中的化學(xué)能通過電化學(xué)反應(yīng)直接轉(zhuǎn)換為電能的發(fā)電裝置.按電解質(zhì)分類,燃料電池一般包括質(zhì)子交換膜燃料電池(Proton Exchange Membrane Fuel Cell,PEMFC)、磷酸燃料電池(Phosphoric Acid Fuel Cell,PAFC)、堿性燃料電池(Alkaline Fuel Cell,AFC)、固體氧化物燃料電池(Solid Oxide Fuel Cell,SOFC)及熔融碳酸鹽燃料電池(Molten Carbonate Fuel Cell,MCFC)等.與火電廠,內(nèi)燃機(jī)和燃?xì)廨啓C(jī)等發(fā)電裝置相比,燃料電池具有能量轉(zhuǎn)化效率高、穩(wěn)定性高、零排放無環(huán)境污染等諸多優(yōu)點(diǎn).同時(shí),由于燃料電池設(shè)備可集中也可分散性配置,在特殊的場合下,燃料電池模塊化的設(shè)置可提供極高的穩(wěn)定性,這也降低了供電系統(tǒng)不安全的風(fēng)險(xiǎn).在所有燃料電池中,堿性燃料電池(AFC)發(fā)展速度最快,主要應(yīng)用于航空航天任務(wù);質(zhì)子交換膜燃料電池(PEMFC)已廣泛應(yīng)用于交通動(dòng)力和小型電源裝置;磷酸燃料電池(PAFC)作為中型電源應(yīng)用進(jìn)入了商業(yè)化階段;熔融碳酸鹽型燃料電池(MCFC)也已完成工業(yè)試驗(yàn)階段;起步較晚的固態(tài)氧化物燃料電池(SOFC)是發(fā)電領(lǐng)域最有應(yīng)用前景的燃料電池.
近年來,有關(guān)燃料電池技術(shù)的新進(jìn)展層出不窮.日本、德國等國家對燃料電池的研發(fā)投入很大,僅汽車制造巨頭用于氫能車的研發(fā)就達(dá)數(shù)億美元,其研發(fā)成果很多都已經(jīng)到了產(chǎn)業(yè)化水平.美國猶他大學(xué)的工程師最近研制出可在室溫下工作的燃料電池,用酶就能使噴氣發(fā)動(dòng)機(jī)燃料產(chǎn)生電能,這種新型燃料電池可以給手持電子設(shè)備、離網(wǎng)型發(fā)電機(jī)和傳感器供電.目前,由于燃料電池中的核心部件“質(zhì)子交換膜”存在燃料滲透等難題,極大限制了醇類燃料電池的大規(guī)模應(yīng)用.中德荷科學(xué)家的研究表明:如果采用石墨烯和氮化硼等單原子層二維材料作為質(zhì)子交換膜,可使現(xiàn)代燃料電池更高效、更安全、更環(huán)保、更輕薄.麻省理工學(xué)院研究人員在評論中指出,本項(xiàng)研究取得的突破性進(jìn)展在理論上已經(jīng)達(dá)到美國能源部設(shè)定的2020年質(zhì)子交換膜輸運(yùn)性能目標(biāo).
本專題得到了衣寶廉院士(中國科學(xué)院大連化學(xué)物理研究所燃料電池工程中心)的大力支持.
·熱點(diǎn)數(shù)據(jù)排行·
截至2015年5月4日,中國知網(wǎng)(CNKI)和Web of Science(WOS)的數(shù)據(jù)報(bào)告顯示,以燃料電池(Fuel Cell)為詞條可以檢索到的期刊文獻(xiàn)分別為2757與22018條,本專題將相關(guān)數(shù)據(jù)按照:研究機(jī)構(gòu)發(fā)文數(shù)、作者發(fā)文數(shù)、期刊發(fā)文數(shù)、被引用頻次進(jìn)行排行,結(jié)果如下.
研究機(jī)構(gòu)發(fā)文數(shù)量排名(CNKI)
研究機(jī)構(gòu)發(fā)文數(shù)量排名(WOS)
作者發(fā)文數(shù)量排名(CNKI)
作者發(fā)文數(shù)量排名(CNKI)
期刊發(fā)文數(shù)量排名(CNKI)
期刊發(fā)文數(shù)量排名(WOS)
根據(jù)中國知網(wǎng)(CNKI)數(shù)據(jù)報(bào)告,以燃料電池(Fuel Cell)為詞條可以檢索到的高被引論文排行結(jié)果如下.
國內(nèi)數(shù)據(jù)庫高被引論文排行
根據(jù)Web of Science統(tǒng)計(jì)數(shù)據(jù),以燃料電池(Fuel Cell)為詞條可以檢索到的高被引論文排行結(jié)果如下.
國外數(shù)據(jù)庫高被引論文排行
·經(jīng)典文獻(xiàn)推薦·
基于Web of Science檢索結(jié)果,利用Histcite軟件選取LCS(Local Citation Score,本地引用次數(shù))TOP 30文獻(xiàn)作為節(jié)點(diǎn)進(jìn)行分析,得到本領(lǐng)域推薦的經(jīng)典文獻(xiàn)如下.
來源出版物:Journal of the Electrochemical Society, 1991, 138(8): 2334-2342
A Mathematical-Model of the Solid-Polymer-Electrolyte Fuel-Cell
Bernardi, DM; Verbrugge, MW
Abstract: We present a mathematical model of the solid-polymer-electrolyte fuel cell and apply it to (i)investigate factors that limit cell performance and (ii)elucidate the mechanism of species transport in the complex network of gas, liquid, and solid phases of the cell. Calculations of cell polarization behavior compare favorably with existing experimental data. For most practical electrode thicknesses,model results indicate that the volume fraction of the cathode available for gas transport must exceed 20% in order to avoid unacceptably low cell-limiting current densities. It is shown that membrane dehydration can also pose limitations on operating current density;circumvention of this problem by appropriate membrane and electrode design and efficient water-management schemes is discussed. Our model results indicate that for a broad range of practical current densities there are no external water requirements because the water produced at the cathode is enough to satisfy the water requirement of the membrane. Inefficiencies due to the transport of unreacted hydrogen or oxygen through the membrane are shown to be insignificant at practical operating current densities. The transport of gases dissolved in the membrane phase, however, limits the utilization of catalyst. Predictions of cell performance with different types of membranes are also examined, and the model results compare favorably with experimental data.
來源出版物:Journal of the Electrochemical Society, 1992, 139(9): 2477-2491
Two-phase flow and transport in the air cathode of proton exchange membrane fuel cells
Wang, ZH; Wang, CY; Chen, KS
Abstract: Two-phase flow and transport of reactants and products in the air cathode of proton exchange membrane (PEM)fuel cells is studied analytically and numerically. Single- and two-phase regimes of water distribution and transport are classified by a threshold current density corresponding to first appearance of liquid water at the membrane/cathode interface. When the cell operates above the threshold current density, liquid water appears and a two-phase zone forms within the porous cathode. A two-phase, multicomponent mixture model in conjunction with a finite-volume-based computational fluid dynamics (CFD)technique is applied to simulate the cathode operation in this regime. The model is able to handle the situation where a single-phase region co-exists with a two-phase zone in the air cathode. For the first time, the polarization curve as well as water and oxygen concentration distributions encompassing both single- and two-phaseregimes of the air cathode are presented. Capillary action is found to be the dominant mechanism for water transport inside the two-phase zone of the hydrophilic structure. The liquid water saturation within the cathode is predicted to reach 6.3% at 1.4 A cm-2for dry inlet air.
Keywords: two-phase transport; PEM fuel cells; analytical modeling; numerical simulation; water management
來源出版物:Journal of Power Sources, 2001, 94(1): 40-50
A Water and Heat Management Model for Proton-Exchange-Membrane Fuel-Cells
Nguyen, TV; White, RE
Abstract: Proper water and heat management are essential for obtaining high-power-density performance at high energy efficiency for proton-exchange-membrane fuel cells. A water and heat management model was developed and used to investigate the effectiveness of various humidification designs. The model accounts for water transport across the membrane by electro-osmosis and diffusion, heat transfer from the solid phase to the gas phase and latent heat associated with water evaporation and condensation in the flow channels. Results from the model showed that at high current densities (>1 A/cm2)ohmic loss in the membrane accounts for a large fraction of the voltage loss in the cell and back diffusion of water from the cathode side of the membrane is insufficient to keep the membrane hydrated (i.e. conductive). Consequently, to minimize this ohmic loss the anode stream must be humidified, and when air is used instead of pure oxygen the cathode stream must also be humidified.
Keywords: mathematical-model; acid membranes; transport
來源出版物:Journal of the Electrochemical Society, 1993, 140(8): 2178-2186
Two-dimensional model for proton exchange membrane fuel cells
Gurau, V; Liu, HT; Kakac, S
Abstract: A 2-D mathematical model for the entire sandwich of a proton-exchange membrane fuel cell including the gas channels was developed. The self-consistent model for porous media was used for the equations describing transport phenomena in the membrane,catalyst layers, and gas diffusers, while standard equations of Navier-Stokes, energy transport, continuity, and species concentrations are solved in the gas channels. A special handling of the transport equations enabled us to use the same numerical method in the unified domain consisting of the gas channels, gas diffusers, catalyst layers and membrane. It also eliminated the need to prescribe arbitrary or approximate boundary conditions at the interfaces between different parts of the fuel cell sandwich. By solving transport equations, as well as the equations for electrochemical reactions and current density with the membrane phase potential, polarization curves under various operating conditions were obtained. Modeling results compare very well with experimental results from the literature. Oxygen and water vapor mole fraction distributions in the coupled cathode gas channel-gas diffuser were studied for various operating current densities. Liquid water velocity distributions in the membrane and influences of various parameters on the cell performance were also obtained.
Keywords: polymer-electrolyte; mathematical-model; oxygen reduction; platinum
來源出版物:AIChE Journal, 1998, 44(11): 2410-2422
·推薦綜述·
燃料電池技術(shù)發(fā)展現(xiàn)狀與展望*
侯明,衣寶廉
(中國科學(xué)院大連化學(xué)物理研究所,遼寧大連116023)
1燃料電池工作原理與分類
燃料電池(Fuel Cell,F(xiàn)C)是把燃料中的化學(xué)能通過電化學(xué)反應(yīng)直接轉(zhuǎn)換為電能的發(fā)電裝置.按電解質(zhì)分類,燃料電池一般包括質(zhì)子交換膜燃料電池(Proton Exchange Membrane Fuel Cell,PEMFC)、磷酸燃料電池(Phosphoric Acid Fuel Cell,PAFC)、堿性燃料電池(Alkaline Fuel Cell,AFC)、固體氧化物燃料電池(Solid Oxide Fuel Cell,SOFC)及熔融碳酸鹽燃料電池(Molten Carbonate Fuel Cell,MCFC)等.以質(zhì)子交換膜燃料電池為例,主要部件包括:膜電極組件(Membrane Electrode Assembly,MEA)、雙極板及密封元件等.膜電極組件是電化學(xué)反應(yīng)的核心部件,由陰陽極多孔氣體擴(kuò)散電極和電解質(zhì)隔膜組成.電解質(zhì)隔膜兩側(cè)分別發(fā)生氫氧化反應(yīng)與氧還原反應(yīng),電子通過外電路做功,反應(yīng)產(chǎn)物為水.額定工作條件下,一節(jié)單電池工作電壓僅為0.7 V左右.為了滿足一定應(yīng)用背景的功率需求,燃料電池通常由數(shù)百個(gè)單電池串聯(lián)形成燃料電池堆或模塊.因此,與其它化學(xué)電源一樣,燃料電池的均一性非常重要.燃料電池發(fā)電原理與原電池類似,但與原電池和二次電池比較,需要具備一相對復(fù)雜的系統(tǒng),通常包括燃料供應(yīng)、氧化劑供應(yīng)、水熱管理及電控等子系統(tǒng),其工作方式與內(nèi)燃機(jī)類似.理論上只要外部不斷供給燃料與氧化劑,燃料電池就可以持續(xù)發(fā)電.
燃料電池從發(fā)明至今已經(jīng)經(jīng)歷了100多年的歷程.由于能源與環(huán)境已成為人類社會(huì)賴以生存的重點(diǎn)問題,近20年以來,燃料電池這種高效、潔凈的能量轉(zhuǎn)化裝置得到了各國政府、開發(fā)商及研究機(jī)構(gòu)的普遍重視.燃料電池在交通運(yùn)輸、便攜式電源、分散電站、航空/天及水下潛器等民用與軍用領(lǐng)域展現(xiàn)出廣闊的應(yīng)用前景.目前,燃料電池汽車、電站及便攜式電源等均處于示范階段,在商業(yè)化道路上還需要解決成本、壽命等一些瓶頸問題.成本和壽命是相互聯(lián)系的,同時(shí)滿足兩者需求是實(shí)現(xiàn)民用燃料電池應(yīng)用所面臨的主要挑戰(zhàn).航天飛機(jī)、潛艇動(dòng)力用燃料電池目前國際上均已應(yīng)用,在只側(cè)重壽命、可靠性的特殊領(lǐng)域,現(xiàn)有燃料電池技術(shù)是可以滿足應(yīng)用需求的.因此,根據(jù)不同的應(yīng)用背景采用不同的技術(shù)路線,是制定燃料電池技術(shù)發(fā)展戰(zhàn)略的重要基礎(chǔ).
2燃料電池的應(yīng)用
2.1航天領(lǐng)域
早在上個(gè)世紀(jì)60年代,燃料電池就成功地應(yīng)用于航天技術(shù),這種輕質(zhì)、高效的動(dòng)力源一直是美國航天技術(shù)的首選.以燃料電池為動(dòng)力的Gemini宇宙飛船1965年研制成功,采用的是聚苯乙烯磺酸膜,完成了8天的飛行.由于這種聚苯乙烯磺酸膜穩(wěn)定性較差,后來在Apollo宇宙飛船采用了堿性電解質(zhì)燃料電池,從此開啟了燃料電池航天應(yīng)用的新紀(jì)元.在Apollo宇宙飛船1966年至1978年服役期間,總計(jì)完成了18次飛行任務(wù),累積運(yùn)行超過了10000 h,表現(xiàn)出良好的可靠性與安全性.除了宇宙飛船外,燃料電池在航天飛機(jī)上的應(yīng)用是航天史上又一成功的范例.美國航天飛機(jī)載有3個(gè)額定功率為12 kW的堿性燃料電池,每個(gè)電堆包含96節(jié)單電池,輸出電壓為28 V,效率超過70%.單個(gè)電堆可以獨(dú)立工作,確保航天飛機(jī)安全返航,采用的是液氫、液氧系統(tǒng),燃料電池產(chǎn)生的水可以供航天員飲用.從1981年首次飛行直至2011年航天飛機(jī)宣布退役,在30年期間里燃料電池累積運(yùn)行了101000 h,可靠性達(dá)到99%以上.
中國科學(xué)院大連化學(xué)物理研究所早在70年代就成功研制了以航天應(yīng)用為背景的堿性燃料電池系統(tǒng),A型額定功率為500 W,B型額定功率為300 W,燃料分別采用氫氣和肼在線分解氫,整個(gè)系統(tǒng)均經(jīng)過環(huán)境模擬實(shí)驗(yàn),接近實(shí)際應(yīng)用.這一航天用燃料電池研制成果,為我國此后燃料電池在航天領(lǐng)域應(yīng)用奠定了一定的技術(shù)基礎(chǔ).
2.2潛艇方面
燃料電池作為潛艇AIP(Air-Independent Propulsion, AIP)動(dòng)力源,從2002年第一艘燃料電池AIP潛艇下水至今已經(jīng)有6艘在役,還有一些FC-AIP潛艇在建造中.2009年10月意大利軍方訂購的2艘改進(jìn)型FC-AIP潛艇開始建造,潛艇水面排水量為1450噸,總長為56 m,最大直徑為7 m,額定船員24名,水下最大航速為20節(jié),計(jì)劃在2015—2016年開始服役.FC-AIP潛艇具有續(xù)航時(shí)間長、安靜、隱蔽性好等優(yōu)點(diǎn),通常柴油機(jī)驅(qū)動(dòng)的潛艇水下一次潛航時(shí)間僅為2天,而FC-AIP潛艇一次潛航時(shí)間可達(dá)3周.這種潛艇用燃料電池是由西門子公司制造,采用鍍金金屬雙極板.212型艇裝載了額定功率為34 kW的燃料電池模塊,214型艇裝載了120 kW燃料電池模塊,2種型號的燃料電池模塊參數(shù),額定工況下效率接近60%.
3燃料電池示范
除了上述實(shí)際應(yīng)用外,燃料電池還在多個(gè)領(lǐng)域展現(xiàn)了不同規(guī)模的示范,包括電動(dòng)汽車、電站、應(yīng)急不間斷電源、便攜式電源及充電器等.在這些領(lǐng)域,燃料電池展示了一定的應(yīng)用前景.示范的目的是發(fā)現(xiàn)問題并解決問題,不斷完善技術(shù),使之逐步接近商業(yè)化目標(biāo).
3.1電動(dòng)汽車
隨著汽車保有量的增加,傳統(tǒng)燃油內(nèi)燃機(jī)汽車造成的環(huán)境污染日益加劇,同時(shí),也面臨著對石油的依存度日益增加的嚴(yán)重問題.燃料電池作為汽車動(dòng)力源是解決因汽車而產(chǎn)生的環(huán)境、能源問題的可行方案之一,近20年來得到各國政府、汽車企業(yè)、研究機(jī)構(gòu)的普遍重視.燃料電池汽車示范在國內(nèi)外不斷興起,較著名的是歐洲城市清潔交通示范項(xiàng)目(Clean Urban Transport for Europe,CUTE),第1期共有27輛車在9個(gè)歐洲城市運(yùn)行2年;并于2006—2009年進(jìn)行第2期示范(Hy-Fleet: CUTE),33輛燃料電池客車在包括北京的10個(gè)城市運(yùn)行;整個(gè)項(xiàng)目累計(jì)運(yùn)行140000 h,行駛約2100000 km,承載乘客約850萬;目前,正在著手進(jìn)行第3期(Clean Hydrogen in European cities project,CHIC)示范.代表性的車型是由Daimler公司制造的燃料電池客車Citaro,分別采用純?nèi)剂想姵?、燃料電池與蓄電池混合動(dòng)力,加拿大Ballard公司提供燃料電池模塊,電堆采用模壓石墨雙極板,具有較好的操作彈性.
通過示范,車用燃料電池技術(shù)取得了長足的進(jìn)展.近年來,燃料電池汽車在性能、壽命與成本方面均取得一定的突破.在性能方面,美國GM公司的燃料電池發(fā)動(dòng)機(jī)體積比功率已與傳統(tǒng)的四缸內(nèi)燃機(jī)相當(dāng),德國Daimler公司通過3輛B型Mercedes-Benz燃料電池轎車F-Cell的環(huán)球旅行向世人展示了燃料電池汽車的可使用性,其續(xù)駛里程、最高時(shí)速、加速性能等已與傳統(tǒng)汽油車相當(dāng),計(jì)劃2014年開始實(shí)施批量生產(chǎn);在壽命方面,美國UTC Power公司的燃料電池客車至2011年8月已經(jīng)累積運(yùn)行了10000 h,壽命指標(biāo)已達(dá)到商業(yè)化目標(biāo);在成本方面,各大汽車公司都致力于降低燃料電池Pt用量,經(jīng)過不斷地技術(shù)改進(jìn),美國GM公司一臺(tái)94 kW的發(fā)動(dòng)機(jī),Pt用量從上一代的80 g降低到30 g,并計(jì)劃2015年P(guān)t用量再降低至1/3,達(dá)到每輛車Pt用量10 g.日本Toyota公司也宣布燃料電池發(fā)動(dòng)機(jī)催化劑Pt用量降低到原來的1/3,預(yù)計(jì)2015年單車成本降低至50000美元,并計(jì)劃于2015年實(shí)現(xiàn)燃料電池汽車商業(yè)化.
我國燃料電池汽車,自“九五”末期第一臺(tái)燃料電池中巴車的問世,到“十一五”2008年北京奧運(yùn)會(huì)和2010年上海世博會(huì)燃料電池汽車的示范運(yùn)行,十幾年的發(fā)展,燃料電池電動(dòng)汽車技術(shù)取得了可喜的進(jìn)步.在北京奧運(yùn)會(huì)上,燃料電池轎車成為“綠色車隊(duì)”中的重要成員.20輛帕薩特“領(lǐng)馭”燃料電池轎車為北京奧運(yùn)會(huì)提供了交通服務(wù),單車無故障行駛里程達(dá)到了5200 km;在上海世博會(huì)上,包括100輛觀光車、90輛轎車和6輛大巴車,總計(jì)196輛燃料電池汽車完成了歷時(shí)6個(gè)月的示范運(yùn)行.其中,100輛觀光車是由國內(nèi)研制,裝有5 kW燃料電池系統(tǒng).70輛轎車裝載的是國內(nèi)研發(fā)的燃料電池系統(tǒng),分別采用55 kW和33 kW兩種類型的燃料電池發(fā)動(dòng)機(jī),前者是常規(guī)電-電混合模式,后者是Plug-in模式,平均單車運(yùn)行里程4500~5000 km,最長的單車運(yùn)行累積里程達(dá)到10191 km.3輛大巴車裝載的是863“節(jié)能與新能源汽車重大項(xiàng)目”資助的80 kW燃料電池發(fā)動(dòng)機(jī),累積運(yùn)行了15674 km,最長單車?yán)锍虨?600 km.此外,還參加了北京公交車示范運(yùn)行以及國際一些示范或賽事,包括國際清潔能源Bibendum大賽、美國加州示范及新加坡世青賽等,展示了中國燃料電池技術(shù)的進(jìn)步.目前,燃料電池發(fā)動(dòng)機(jī)技術(shù)明顯提升,在中國科技部支持下,國產(chǎn)PEMFC關(guān)鍵材料和部件的開發(fā)取得了重大進(jìn)展,研制成功了高導(dǎo)電性及優(yōu)化孔結(jié)構(gòu)的碳紙、增強(qiáng)型復(fù)合質(zhì)子交換膜、高穩(wěn)定性/高活性Pt-Pd復(fù)合電催化劑及薄型全金屬雙極板等.經(jīng)過膜電極技術(shù)的優(yōu)化,電催化劑利用率得到大幅提高,流場優(yōu)化提高了高電流密度下水管理能力,使額定工作點(diǎn)由0.66 V@0.5 A·cm-2提升至0.66 V@1.0 A·cm-2,比功率達(dá)到1300 W·L-1(新源動(dòng)力提供),在同樣功率輸出情況下,體積和質(zhì)量分別減小了一半.
3.2燃料電池固定式分散電站
污染重、能效低一直是困擾火力發(fā)電的核心問題,燃料電池作為低碳、減排的清潔發(fā)電技術(shù),受到國內(nèi)外的普遍重視.燃料電池電站不同于燃料電池汽車,沒有頻繁啟動(dòng)問題,因此可以采用以下4種燃料電池技術(shù),分別是磷酸燃料電池、質(zhì)子交換膜燃料電池、固體氧化物燃料電池和熔融碳酸鹽燃料電池.
PAFC電站代表性的開發(fā)商是UTC Power公司,其開發(fā)的PureCell○RModel系列200 kW和400 kW磷酸燃料電池發(fā)電系統(tǒng),20年多年里已經(jīng)在19個(gè)國家安裝運(yùn)行近300臺(tái),部分電站運(yùn)行已經(jīng)超過40000 h的設(shè)計(jì)壽命.發(fā)電系統(tǒng)以天然氣為原料,由燃料處理、燃料電池模塊及電調(diào)節(jié)與控制3個(gè)部分組成,電效率接近40%(LHV).若計(jì)入熱回收,總效率可以接近80%~90%(LHV).磷酸燃料電池電站在技術(shù)上發(fā)展比較成熟,但由于使用貴金屬催化劑,大規(guī)模商業(yè)化還面臨成本高的瓶頸問題.
PEMFC電站的代表性開發(fā)商是Ballard公司,主要開發(fā)250 kW~1 MW的示范電站,目前示范數(shù)量還不多,國內(nèi)華南理工大學(xué)也進(jìn)行了300 kW PEMFC電站的示范.質(zhì)子交換膜燃料電池用于固定電站與用于燃料電池汽車相比,由于工況相對緩和,不需要像燃料電池汽車那樣頻繁變載,避免了動(dòng)態(tài)工況引起的燃料電池材料衰減,相對延長了壽命.但是,成本問題還是PEMFC電站商業(yè)化面臨的主要問題.另外,由于PEMFC的操作溫度在80~90℃之間,故其熱品質(zhì)比較低,熱量回收效率不高,影響整體燃料利用率.再有,為了防止PEMFC燃料電池中毒,燃料需要凈化,會(huì)增加一部分成本.高溫質(zhì)子交換膜燃料電池(HTPEMFC)操作溫度可以達(dá)到150~200℃,一定程度上可以緩解上述問題,目前HT-PEMFC技術(shù)還處于研發(fā)中.
Siemens Westinghouse公司開發(fā)了固體氧化物燃料電池電站,以陰極作支撐的管式SOFC 機(jī)械強(qiáng)度高,熱循環(huán)性能好,易于組裝與管理.自2000年以來,西門子-西屋公司已建成多臺(tái)大型100~250 kW分散電站進(jìn)行試驗(yàn)運(yùn)行,其中以天然氣為燃料的100 kW SOFC 系統(tǒng)總計(jì)運(yùn)行20000 h,220 kW SOFC與燃?xì)廨啓C(jī)聯(lián)合發(fā)電系統(tǒng)效率可達(dá)到60%~70%.但現(xiàn)有的技術(shù)如電化學(xué)氣相沉積和多次高溫?zé)Y(jié)等導(dǎo)致陰極支撐型SOFC電池成本過高、難以推廣.借助廉價(jià)的濕化學(xué)法、等離子噴涂等技術(shù)替代電化學(xué)氣相沉積制備電解質(zhì)薄膜,并運(yùn)用改進(jìn)燒結(jié)工藝、減少燒結(jié)次數(shù)等手段,有望達(dá)到大幅度降低陰極支撐管型SOFC成本的目的.
MCFC電站,美國Fuel Cell Energy公司處于國際領(lǐng)先地位,其開發(fā)的MCFC電站已在全球裝機(jī)60余臺(tái),主要用于醫(yī)院、賓館、大學(xué)及廢水處理廠等場所示范發(fā)電.MCFC操作溫度較高(650~700℃),可以實(shí)現(xiàn)熱電聯(lián)供及與氣輪機(jī)聯(lián)合循環(huán)發(fā)電,以進(jìn)一步提高燃料的能量轉(zhuǎn)化效率.由于熔鹽的強(qiáng)腐蝕性以及高溫對材料是一個(gè)挑戰(zhàn),壽命是MCFC要解決的關(guān)鍵問題.
3.3備用電源與家庭電源
與現(xiàn)有的柴油發(fā)電機(jī)比較,燃料電池作為不間斷備用電源,具有高密度、高效率、長待時(shí)及環(huán)境友好等特點(diǎn),可以為電信、銀行等重要部門或偏遠(yuǎn)地區(qū)提供環(huán)保型電源.家庭與一些公共場所大多采用1~5 kW小型熱電聯(lián)供裝置,家庭電源通常以天然氣為燃料,這樣可以兼容現(xiàn)有的公共設(shè)施,提供電網(wǎng)以外的電,廢熱可以以熱水的形式利用,備用電源也可采用甲醇液體燃料.在燃料電池電源產(chǎn)品研發(fā)方面,日本的Ebara-Ballard公司1 kW家庭型燃料電池電源,其產(chǎn)品已經(jīng)在700多個(gè)場所試驗(yàn),并建立了年產(chǎn)4000臺(tái)的生產(chǎn)基地;美國Idatech公司研制的5 kW UPS已于2008年拿到印度ACME集團(tuán)30000臺(tái)的訂單;美國Plug Power公司已實(shí)現(xiàn)近千臺(tái)的5 kW電源的銷售,主要用于通訊、軍事等方面;此外,Relion與Altergy公司也開拓了燃料電池備用電源市場(圖9B).我國也已研制了10 kW的供電系統(tǒng),以家庭用電為示范,已經(jīng)運(yùn)行了2500 h.
3.4燃料電池可移動(dòng)電源、充電器
燃料電池作為小型可移動(dòng)電源或二次電池的充電器,也是目前研發(fā)的熱點(diǎn).主要技術(shù)基礎(chǔ)是采用直接甲醇燃料電池,即以甲醇為燃料,這種液體燃料具有攜帶方便、比能量高等特點(diǎn).直接甲醇燃料電池初期是瞄準(zhǔn)手機(jī)、筆記本電腦電源市場,旨在提供長待時(shí)電池,但由于在系統(tǒng)管理、小型化等技術(shù)方面還有待突破,近期人們又把目光集中到了充電器市場.東芝公司2009年發(fā)布了甲醇燃料電池充電器產(chǎn)品DynarioTM,可為手機(jī)等電子器件充電,以滿足手機(jī)日益增加的多功能化需求.經(jīng)由USB接口在20 s內(nèi)可為一部手機(jī)充電,燃料罐14 mL儲(chǔ)存高濃度甲醇,可以充2部常規(guī)手機(jī).該產(chǎn)品已經(jīng)通過了國際電工協(xié)會(huì)(International Electrotechnical Commission, IEC)的安全標(biāo)準(zhǔn),首次試售3000部,收集用戶反饋意見與市場反應(yīng)以便進(jìn)行改進(jìn).國內(nèi)也研制成功了多功能直接甲醇燃料電池充電器,為野外移動(dòng)通訊設(shè)備等供電,其工作時(shí)間可從原來的幾個(gè)小時(shí)提高到1~3天.經(jīng)過環(huán)境模擬試驗(yàn),表現(xiàn)出良好的環(huán)境適應(yīng)性和可使用性.此外,直接甲醇燃料電池在軍民微小型可移動(dòng)電源領(lǐng)域也展示了廣闊的應(yīng)用前景.國內(nèi)研制的額定輸出功率為25~50 W的DMFC移動(dòng)電源系統(tǒng),經(jīng)同行專家現(xiàn)場測試表明,能量密度達(dá)502 Wh·kg-1,約為鋰離子電池的3倍.隨著現(xiàn)代化戰(zhàn)爭裝備的日益先進(jìn),單兵作戰(zhàn)需要更多電子裝備,直接甲醇燃料電池可在單兵作戰(zhàn)電源發(fā)揮優(yōu)勢.美國陸軍開發(fā)了型號為M-25燃料電池單兵電源,用于數(shù)字通訊、GPS等電子裝備.經(jīng)過實(shí)際測試表明,這種電池可以在平均20W功率下使用72 h,而質(zhì)量比傳統(tǒng)電池降低了80%.該項(xiàng)目得到美國陸軍采辦挑戰(zhàn)項(xiàng)目總計(jì)約3億美元的資助.此外,供陸軍指揮系統(tǒng)的無線電衛(wèi)星通訊、遠(yuǎn)程監(jiān)控裝置等微小型移動(dòng)電源也引起各國的普遍關(guān)注.目前,直接甲醇燃料電池在技術(shù)方面還需要進(jìn)一步解決壽命、穩(wěn)定性等關(guān)鍵問題,性能有待進(jìn)一步提升.重點(diǎn)是通過研制新型的阻醇膜、多元合金催化劑以及調(diào)變膜電極組件結(jié)構(gòu)等,解決材料在運(yùn)行過程中的穩(wěn)定性與耐久性、系統(tǒng)水熱管理等問題,并同時(shí)解決工程化實(shí)際問題,使DMFC在充電器與可移動(dòng)電源等領(lǐng)域盡早實(shí)現(xiàn)商業(yè)化.
4燃料電池技術(shù)發(fā)展思路
如上所述,燃料電池應(yīng)用主要集中在潛艇、航天等特殊領(lǐng)域,且技術(shù)已相對成熟.而民用領(lǐng)域如燃料電池電動(dòng)汽車、電站等尚處于示范階段,相關(guān)技術(shù)距離商業(yè)化還有一定的差距,存在著成本、壽命等瓶頸問題.其原因可以歸結(jié)為民用產(chǎn)品與特殊應(yīng)用產(chǎn)品對成本承受力的差異.特殊領(lǐng)域由于面對的是特殊應(yīng)用,對成本目標(biāo)沒有苛刻的要求,而民用產(chǎn)品面對的是廣大消費(fèi)群體,低成本是應(yīng)用的前提條件.民用產(chǎn)品在追求低成本的同時(shí),壽命也面臨著挑戰(zhàn),如減少Pt用量雖可降低燃料電池成本,但低Pt催化劑電池的耐久性卻更加嚴(yán)峻.因此,兼顧低成本與長壽命是實(shí)現(xiàn)燃料電池民用產(chǎn)品商業(yè)化要解決的關(guān)鍵問題.以催化劑為例,特殊領(lǐng)域貴金屬催化劑擔(dān)載量是民用產(chǎn)品的1~2個(gè)數(shù)量級,因而它的抗衰減能力比民用產(chǎn)品大大提高,燃料電池所面臨的壽命問題也會(huì)迎刃而解.因此,現(xiàn)階段我國一方面要大力推進(jìn)燃料電池在特殊領(lǐng)域的應(yīng)用,力爭占領(lǐng)未來此領(lǐng)域動(dòng)力源的制高點(diǎn);另一方面要促進(jìn)燃料電池在民用領(lǐng)域的技術(shù)進(jìn)步,加快燃料電池民用產(chǎn)品的商業(yè)化步伐.
4.1提高性能與可靠性,加快我國燃料電池技術(shù)在特殊領(lǐng)域的應(yīng)用
1)航空航天
燃料電池在航天領(lǐng)域的應(yīng)用,除了前面敘述的在Apollo航天飛機(jī)等的成功應(yīng)用外,以燃料電池為動(dòng)力的平流層飛艇、無人機(jī)等也成為國際研發(fā)熱點(diǎn),燃料電池在航天領(lǐng)域已展示了廣闊的應(yīng)用前景.
在航天技術(shù)中,高比能量是追求的重要指標(biāo)之一.目前,有2條技術(shù)路線,一是采用氫/氧或氫/空燃料電池技術(shù),即利用攜帶的氫氣與氧氣或空壓機(jī),提供一定航程所需的燃料與氧化劑;另一種是依據(jù)可再生燃料電池技術(shù)(Regenerative Fuel Cell, RFC),即飛行器向日時(shí)由太陽能電池提供動(dòng)力同時(shí)電解水生成氫氣與氧氣,背日時(shí)電解產(chǎn)物氫和氧使燃料電池發(fā)電作為飛行器動(dòng)力源.氫/氧燃料電池重點(diǎn)解決的是燃料和氧化劑的攜帶與燃料電池耦合技術(shù);氫/空燃料電池的瓶頸技術(shù)是高效空壓機(jī),目前國內(nèi)這方面技術(shù)還處于研發(fā)過程中.相比之下,可再生燃料電池在航天技術(shù)方面的應(yīng)用引起人們更多的重視,尤其是一體化RFC技術(shù),使系統(tǒng)集成更加緊湊,有利于提高系統(tǒng)比能量.
再生燃料電池由于電解過程需要較高的電位(1.5~1.8 V),對燃料電池材料是一個(gè)挑戰(zhàn).其中導(dǎo)電、耐腐蝕兼容的雙極板與擴(kuò)散層材料是研發(fā)的重點(diǎn),如輕質(zhì)的Ti雙極板與多孔Ti擴(kuò)散層材料在高電位下具有較高的耐腐蝕性,但是原材料表面接觸電阻較大,需要經(jīng)過表面處理.使用貴金屬Pt、Au等可增加導(dǎo)電和耐腐蝕性,然而成本較高.其它的替代方案目前正在研究中.為了提高系統(tǒng)比能量,需要燃料與氧化劑5~10 MPa高壓儲(chǔ)存,因此RFC的高壓水電解技術(shù)更應(yīng)重點(diǎn)關(guān)注.除了高壓要求的電解池硬件強(qiáng)度及密封問題外,高壓下氣液兩相流動(dòng)的傳遞過程對電化學(xué)反應(yīng)的影響也需進(jìn)行研究.為了提高系統(tǒng)比能量,RFC系統(tǒng)水管理和熱管理也應(yīng)當(dāng)進(jìn)一步改進(jìn),如采用無泵水循環(huán)技術(shù)可減少系統(tǒng)部件、減輕質(zhì)量,采用熱解石墨或熱泵技術(shù)可以實(shí)現(xiàn)更加高效排熱.
目前RFC可分為燃料電池和電解池分體式和一體式2種.分體式技術(shù)比較成熟,一體式技術(shù)還處于研究階段,關(guān)鍵是雙效氧電極技術(shù),一體式RFC研制成功可極大地提高系統(tǒng)比功率與比能量.此外,為了適應(yīng)空間環(huán)境,動(dòng)力系統(tǒng)的環(huán)境適應(yīng)性也要特別考慮.可根據(jù)環(huán)境實(shí)驗(yàn)項(xiàng)目,作RFC電池與系統(tǒng)的結(jié)構(gòu)設(shè)計(jì),以滿足空間應(yīng)用的需求.
2)水下潛器
水下應(yīng)用燃料電池除了能給潛艇提供安靜、長航時(shí)的動(dòng)力源系統(tǒng)外,還可以用于水下機(jī)器人、水下蛙人等動(dòng)力源.
水下燃料電池均以氫氧燃料電池技術(shù)為基礎(chǔ),其中排水與零排放技術(shù)是目前研究的熱點(diǎn).燃料電池生成水在陰極側(cè),在氫-空燃料電池中可以通過氣體吹掃與夾帶把生成水排出燃料電池,以保證電池安全可靠運(yùn)行.但在以氧氣為氧化劑的情況下,按給定的反應(yīng)計(jì)量比,氧氣的體積僅為空氣的1/5,如此必將減弱生成水的排出能力,導(dǎo)致電池發(fā)生“水淹”,不能正常運(yùn)行.采用氫氧尾氣循環(huán)和內(nèi)部排水技術(shù)等可實(shí)現(xiàn)氫氧燃料電池的有效排水.
水下操作更苛刻的要求是零排放.目前,零排放技術(shù)有2種,一種是氫氧吸收技術(shù),另一種是氫氧復(fù)合技術(shù).氫氧吸收是利用儲(chǔ)氫、儲(chǔ)氧材料,把尾排的氫氧儲(chǔ)存起來,但其儲(chǔ)存量受儲(chǔ)罐容積限制;氫氧復(fù)合是利用催化作用把排出的少量氫、氧復(fù)合生成水,達(dá)到零排放目的.在氫氧復(fù)合技術(shù)中,控制好氫氧化學(xué)反應(yīng)計(jì)量比是關(guān)鍵.另外氫氧復(fù)合催化劑在有水生成情況下的穩(wěn)定性也是要關(guān)注的問題.
在水下用燃料電池系統(tǒng)中,氫氣供給有多種方式,如金屬固態(tài)儲(chǔ)氫、高壓氣態(tài)儲(chǔ)氫、低溫液態(tài)儲(chǔ)氫以及甲醇重整制氫等.可根據(jù)不同的應(yīng)用背景選擇不同的儲(chǔ)氫技術(shù),如水下機(jī)器人通常優(yōu)先選擇高壓氣態(tài)高純氫以滿足一定的續(xù)航里程;而潛艇比較成熟的技術(shù)還局限于使用金屬固態(tài)儲(chǔ)氫,其中儲(chǔ)放氫過程的能量須與燃料電池耦合;對甲醇重整制氫過程,也要考慮制氫過程與燃料電池發(fā)電過程的熱平衡,以提高整個(gè)系統(tǒng)的工作效率.
水下燃料電池系統(tǒng)部件模塊化是提高可靠性的重要措施,一個(gè)動(dòng)力系統(tǒng)可以由多個(gè)模塊并、串聯(lián)而成,當(dāng)一組模塊出現(xiàn)故障,可以瞬間切斷,在線更換,以提供系統(tǒng)長航時(shí)運(yùn)行能力.
4.2解決壽命與成本問題,促進(jìn)民用燃料電池產(chǎn)品的商業(yè)化
燃料電池汽車、電站等民用產(chǎn)品面臨著的低成本與長壽命兼顧問題,是制約商業(yè)化的瓶頸問題.需要從燃料電池材料、部件與系統(tǒng)3方面進(jìn)行改進(jìn)與創(chuàng)新,以促進(jìn)燃料電池盡早走向應(yīng)用.車用燃料電池的問題尤為突出,下面以車用質(zhì)子交換膜燃料電池為例,探討成本與耐久性兼容的解決方案.
1)燃料電池核心材料的創(chuàng)新
① 發(fā)展貴金屬部分替代或完全替代的催化劑改進(jìn)目前使用的Pt/C催化劑是降低成本與提高壽命的關(guān)鍵.研究顯示,由于燃料電池動(dòng)態(tài)工況或高電位會(huì)引起催化劑的團(tuán)聚、流失,從而引起催化劑活性比表面積下降,造成燃料電池性能嚴(yán)重衰減.此外,由于Pt成本較高且資源有限,降低Pt催化劑用量勢在必行.然而在低Pt催化劑研發(fā)的同時(shí),也必須解決相關(guān)的穩(wěn)定性,以期建立低成本、長壽命的最優(yōu)解決方案.
優(yōu)化制備方法,利用形貌控制,可有效地提高催化劑活性與穩(wěn)定性.孫世剛等利用高指數(shù)晶面Pt具有的開放表面結(jié)構(gòu)、高密度的臺(tái)階原子以及其所處的短程有序環(huán)境等特點(diǎn),使催化劑的活性和穩(wěn)定性方面均得到顯著提高.
Pt合金催化劑目前顯示出較好的發(fā)展前景,借助加入第2或第3種非Pt金屬,利用電子或幾何效應(yīng),在達(dá)到低Pt、高活性的同時(shí),穩(wěn)定性也相應(yīng)提高.其中核殼型催化劑是研究熱點(diǎn)之一,利用非貴金屬為支撐核,表面貴金屬為殼的結(jié)構(gòu),可降低Pt用量,提高質(zhì)量比活性.如由欠電位沉積方法制備的Pt-Pd-Co/C單層核殼催化劑總質(zhì)量比活性是商業(yè)催化劑Pt/C的3倍;利用脫合金方法制備的Pt-Cu-Co/C核殼電催化劑,質(zhì)量比活性可達(dá)Pt/C的4倍.此外,Pt催化劑表面的修飾也可以起到提高穩(wěn)定性作用,如以金簇修飾Pt納米粒子,提高了Pt的氧化電勢,起到了抗Pt溶解的作用,經(jīng)過30000次循環(huán)后金修飾的鉑催化劑的活性表面積與初始狀態(tài)相比并沒有明顯降低.
Pt3Pd/C比Pt/C抗衰減能力之所以有較大提高,原因在于加入Pd提高了Pt的氧還原活性,改善了其抗氧化能力.中國科學(xué)院大連化學(xué)物理研究所包信和研究組借助貴金屬Pt表面與單層氧化亞鐵薄膜中鐵原子的強(qiáng)相互作用產(chǎn)生的界面限域效應(yīng),成功構(gòu)建了表面配位不飽和亞鐵結(jié)構(gòu)催化劑,在一氧化碳低溫活化過程中顯示出非常獨(dú)特的催化活性,可高效去除CO毒物,該催化劑在PEMFC實(shí)際工況條件下穩(wěn)定運(yùn)行超過1500 h;最近,又將界面限域的概念擴(kuò)展到PtNi、PtSn、PtCo等催化體系,發(fā)現(xiàn)了界面限域的配位不飽和Ni物種及其在低溫氧化反應(yīng)中的重要作用.
催化劑載體的改進(jìn),也是提高催化劑穩(wěn)定性的有效途徑之一.由于目前Pt催化劑載體大多采用XC-72碳黑,在高電位及電位循環(huán)下會(huì)發(fā)生載體腐蝕,是造成催化劑團(tuán)聚與流失的主要原因.改進(jìn)催化劑載體可以從2個(gè)方面著手,一是改進(jìn)目前的碳載體材料,如高溫石墨化處理、添加官能團(tuán)等方法,可以提高高電位下載體的耐腐蝕性;二是采用新的載體材料,碳納米管或氮摻雜的碳納米管、納米碳須、WxCy、氧化銦錫等碳與非碳載體.這些新型載體材料在一定程度上提高了耐腐蝕性,但是比表面積均遠(yuǎn)低于現(xiàn)有的載體材料.目前具有高導(dǎo)電、高比表面積與高耐蝕性兼顧的載體材料還是研究的難點(diǎn).
在探求低Pt催化劑的同時(shí),非Pt催化劑的研究也一直在進(jìn)行中.如金屬硫族化合物、金屬大環(huán)配合物等展示了較好的初活性,但穩(wěn)定性還遠(yuǎn)滿足不了要求.近期,Lefèvre等在非Pt催化劑的研究方面取得了進(jìn)展,以載量為5.3 mg·cm-2的非貴金屬Fe/N/C電催化劑制備的電極,低電流密度下與Pt載量為0.4 mg·cm-2的Gore電極性能相當(dāng).但因前者擔(dān)載量比Pt催化劑高出幾倍甚至十幾倍,電極厚度隨之增加,從而導(dǎo)致電極反應(yīng)的傳質(zhì)阻力大幅度增加,而且其穩(wěn)定性還需進(jìn)一步改善.此外,近期研究的氮摻雜碳基非Pt催化劑也表現(xiàn)出較高的氧還原反應(yīng)催化活性與穩(wěn)定性.
至今,酸性體系下能使用的非Pt催化劑還沒有突破性進(jìn)展.目前,人們把目光聚集到堿性體系的聚合物燃料電池.由于堿性環(huán)境中的氧還原動(dòng)力學(xué)快于酸性條件,催化劑可實(shí)現(xiàn)貴金屬替代,使燃料電池成本得到根本性的降低.武漢大學(xué)莊林研究組結(jié)合實(shí)驗(yàn)與計(jì)算提出了利用非化學(xué)計(jì)量比金屬氧化物修飾調(diào)控Ni表面電子結(jié)構(gòu),所得Ni基HOR催化劑表面的反應(yīng)選擇性、抗氧化性均大幅度提高,藉此組裝的堿性聚合物電解質(zhì)燃料電池可以完全擺脫對貴金屬催化劑的依賴.目前技術(shù)難點(diǎn)是研究高離子傳導(dǎo)性、高穩(wěn)定性的堿性離子交換膜.一些學(xué)者進(jìn)行了季胺或季膦型聚合物膜的研究,通過對電解質(zhì)可溶性溶劑的選擇,制備出帶有立體化三相界面的非貴金屬催化劑膜電極,但聚合物膜的離子傳導(dǎo)性與穩(wěn)定性還有待于進(jìn)一步提高.
② 進(jìn)一步促進(jìn)高性能、廉價(jià)國產(chǎn)材料的批量供應(yīng)
除了催化劑外,其它材料如質(zhì)子交換膜、碳紙等也是制約成本與壽命的重要因素.其中Nafion系列的均質(zhì)全氟磺酸膜在燃料電池環(huán)境中由于反應(yīng)過程中氫氧自由基的攻擊,發(fā)生衰減,影響電池壽命.此外,該種膜大部分依賴于進(jìn)口,成本較高.因此需要研制新型高穩(wěn)定的國產(chǎn)化質(zhì)子交換膜替代Nafion膜,主要是從提高機(jī)械性能與化學(xué)穩(wěn)定性出發(fā)進(jìn)行改進(jìn).例如采用多孔材料、碳納米管、TiO2納米管等與全氟磺酸樹脂復(fù)合的增強(qiáng)膜,可有效地增強(qiáng)膜的機(jī)械性能,使之在動(dòng)態(tài)工況下,穩(wěn)定性顯著提高.在膜中加入自由基淬滅劑,也可抵抗發(fā)電過程氫氧自由基的攻擊,從而提高化學(xué)穩(wěn)定性.再者,短側(cè)鏈膜因其具有較好的質(zhì)子傳導(dǎo)率及高的穩(wěn)定性也引起了關(guān)注,制備帶自由基淬滅劑的短側(cè)鏈復(fù)合膜是一個(gè)比較有前景的發(fā)展方向.
碳紙目前也是采用進(jìn)口材料,在科技部“863課題”支持下,國產(chǎn)化的替代產(chǎn)品已經(jīng)基本研制成功,其性能已接近國際先進(jìn)水平,有待更進(jìn)一步優(yōu)化及研制批量化生產(chǎn)工藝與設(shè)備,以滿足燃料電池商業(yè)化的需求.高穩(wěn)定性、低成本的國產(chǎn)化材料,是發(fā)展國內(nèi)燃料電池技術(shù)的必由之路.
2)燃料電池關(guān)鍵部件的改進(jìn)
① 高催化劑利用率、性能穩(wěn)定的膜電極技術(shù)除了催化劑本身以外,改進(jìn)、優(yōu)化燃料電池膜電極組件制備方法是有效提高Pt利用率、降低成本的重要手段.國際上已經(jīng)發(fā)展了3代MEA技術(shù)路線:一是把催化層制備到擴(kuò)散層上,通常采用絲網(wǎng)印刷方法,該技術(shù)已經(jīng)成熟;二是把催化層制備到膜上,與第一種方法比較,在一定程度上提高了催化劑的利用率與耐久性;三是有序化的MEA,把催化劑如Pt制備到有序化的納米結(jié)構(gòu)上,使電極呈有序化結(jié)構(gòu),有利于降低大電流密度下的傳質(zhì)阻力,進(jìn)一步提高燃料電池性能,降低催化劑用量.利用有序化MEA制備技術(shù),3M公司研制的納米結(jié)構(gòu)薄膜MEA,其Pt擔(dān)載量可降至0.15~0.25 mg·cm-2,并顯示出較好的性能.
② 高均一性電堆技術(shù)
提高電堆的一致性,提升額定工作點(diǎn)電流密度,也是降低燃料電池Pt用量以及其它硬件成本的重要環(huán)節(jié).車用燃料電池為了滿足一定功率需求,電堆通常都是由數(shù)百節(jié)單電池組成,電堆內(nèi)單電池間的一致性是保證燃料電池能夠高功率運(yùn)行的關(guān)鍵.一致性除了與燃料電池材料、部件加工的均一性有關(guān)外,還與電堆的水、氣、熱分配密切相關(guān).從設(shè)計(jì)、制備及操作3方面出發(fā)進(jìn)行調(diào)控,通過模擬仿真手段研究流場結(jié)構(gòu)、阻力分配對流體分布的影響,找出關(guān)鍵影響因素,重點(diǎn)研究水的傳遞、分配與水生成速率、水傳遞系數(shù)、電極/流場界面能之間的關(guān)系,研究穩(wěn)態(tài)與動(dòng)態(tài)載荷條件對電堆阻力的影響,保證電堆在運(yùn)行過程中保持均一性,從而可以大幅提升額定點(diǎn)工作電流密度以及電堆的功率密度,降低成本.
3)燃料電池系統(tǒng)技術(shù)的完善
① 緩解燃料電池衰減的控制策略
研究發(fā)現(xiàn),動(dòng)態(tài)循環(huán)工況、啟動(dòng)/停車過程、連續(xù)低載或怠速運(yùn)行等都是引起燃料電池衰減的主要原因.針對這些,提出車用燃料電池的合理控制策略,規(guī)避可能引起衰減因素的出現(xiàn),起到保護(hù)材料遭到侵害的作用.燃料電池關(guān)鍵材料的研究需要相對長的時(shí)間,就目前看,可以在現(xiàn)有材料的基礎(chǔ)上通過改變控制策略,以提高其耐久性.
采用二次電池、超級電容器等儲(chǔ)能裝置與燃料電池構(gòu)建電-電混合動(dòng)力,既可減緩燃料電池輸出功率變化速率,又可避免燃料電池載荷的大幅度波動(dòng),以使燃料電池能在相對穩(wěn)定的情況下工作,避免加載瞬間由于空氣饑餓引起的電壓波動(dòng),減緩運(yùn)行過程中因頻繁變載而引起的電位掃描最終導(dǎo)致催化劑的加速衰減.還可采用“前饋”控制策略,即在加載前預(yù)置一定量的反應(yīng)氣,以減輕反應(yīng)氣的饑餓現(xiàn)象.利用輔助負(fù)載限電位法,亦可有效地抑制啟動(dòng)、停車瞬間由于陽極側(cè)易形成氫空界面而產(chǎn)生的高電位.此外,碳腐蝕速率與進(jìn)氣速率密切相關(guān).在啟動(dòng)過程中快速進(jìn)氣可以降低高電位停留時(shí)間,達(dá)到減少碳載體損失的目的.利用混合動(dòng)力控制策略,在低載時(shí)給二次電池充電,提高電池的總功率輸出,也可起到降低電位的目的.此外,美國UTC公司在一個(gè)專利中提出了怠速限電位的方法.通過調(diào)小空氣量、同時(shí)循環(huán)尾排空氣以降低氧濃度的辦法,達(dá)到抑制電位過高的目的.合理的控制策略可實(shí)現(xiàn)燃料電池內(nèi)部有效水管理,保持燃料電池內(nèi)水處在一定的合適范圍,尤其在動(dòng)態(tài)工況下,使水能夠跟蹤動(dòng)態(tài)操作變化,保證燃料電池正常穩(wěn)定工作,避免由于干濕度頻繁變化導(dǎo)致的失效或性能衰減.
② 高比功率、高可靠性的系統(tǒng)集成技術(shù)
目前,國內(nèi)車用燃料電池系統(tǒng)質(zhì)量比功率僅為300 W·kg-1,而國際先進(jìn)水平的系統(tǒng)質(zhì)量比功率已經(jīng)達(dá)到650 W·kg-1.造成差距的主要原因是國際上大多都是汽車制造商在從事燃料電池發(fā)動(dòng)機(jī)的制造,他們利用傳統(tǒng)汽車工業(yè)技術(shù)基礎(chǔ),研制出高集成度的產(chǎn)品.有鑒于此,國內(nèi)燃料電池開發(fā)單位需要與汽車廠開展合作,移植傳統(tǒng)汽車工業(yè)的成熟技術(shù),推進(jìn)燃料電池系統(tǒng)技術(shù)的進(jìn)步,并進(jìn)一步提高部件可靠性,延長無故障間隔時(shí)間,促進(jìn)燃料電池商業(yè)化.
5結(jié)語
燃料電池經(jīng)過近半個(gè)多世紀(jì)的發(fā)展,已經(jīng)實(shí)現(xiàn)了在航天飛機(jī)、宇宙飛船及潛艇等特殊領(lǐng)域的應(yīng)用,而民用方面由于受壽命與成本的制約,至今在電動(dòng)汽車、電站、便攜式電源或充電器等各行業(yè)還處于示范階段.未來我國應(yīng)大力推進(jìn)燃料電池在特殊領(lǐng)域的應(yīng)用,增強(qiáng)我國的國防軍事實(shí)力;同時(shí),要集中解決壽命與成本兼顧問題,從材料、部件、系統(tǒng)等3個(gè)層次進(jìn)行技術(shù)改進(jìn)與創(chuàng)新,加快燃料電池民用商業(yè)化步伐,提供高能效、環(huán)境友好的燃料電池發(fā)電技術(shù),為建立低碳、減排、不依賴于化石能源的能量轉(zhuǎn)化技術(shù)新體系做貢獻(xiàn).
·高被引論文摘要·
被引頻次:243
燃料電池現(xiàn)狀與未來
衣寶廉
簡述了國外燃料電池發(fā)展?fàn)顟B(tài),近年來取得的重要進(jìn)展;尤其是在提高質(zhì)子交換膜型燃料電池的性能、電池組與電池系統(tǒng)的比功率比能量方面的技術(shù)突破,這種電池作為電動(dòng)汽車動(dòng)力源和潛艇AIP推進(jìn)動(dòng)力源應(yīng)用前景和必須解決的主要技術(shù)、經(jīng)濟(jì)問題.熔融碳酸鹽和固體氧化物燃料電池作為區(qū)域性分散電站的可能性和必須解決的技術(shù)問題.簡述了國內(nèi)在燃料電池研究中取得的主要成果和目前發(fā)展?fàn)顟B(tài).簡介了國內(nèi)千瓦級堿性燃料電池和質(zhì)子交換膜燃料電池主要性能,并對國內(nèi)燃料電池發(fā)展提出了參考意見.
燃料電池;堿性氫氧燃料電池;磷酸燃料電池;質(zhì)子交換膜燃料電池;熔融碳酸鹽燃料電池;固體氧化物燃料電池
來源出版物:電源技術(shù),1998, 22(5): 216-221
被引頻次:145
聚合物電解質(zhì)燃料電池的研究進(jìn)展
陳延禧
摘要:綜述了聚合物電解質(zhì)燃料電池(PEMFC)最新的研究進(jìn)展,包括離子交換膜、膜電極結(jié)構(gòu)及工藝、電催化劑、水和熱管理.最后,對我國的PEMFC研究提出了意見.
關(guān)鍵詞:燃料電池;聚合物電解質(zhì)燃料電池;離子交換膜;電催化劑
來源出版物:電源技術(shù),1996, 20(1): 21-27
被引頻次:132
燃料電池概述
劉建國,孫公權(quán)
摘要:燃料電池在固定與分散電站、交通運(yùn)輸、移動(dòng)電源等方面廣闊的應(yīng)用前景現(xiàn)已受到許多研究單位和公司的廣泛關(guān)注.文章簡要介紹了幾種主要類型燃料電池(堿性燃料電池alkaline fuel cell, AFC)、磷酸燃料電池(phosphoric acid fuel cell, PAFC)、熔融碳酸鹽燃料電池(molten carbonate fuel cell, MCFC)、固體氧化物燃料電池(solid oxide fuel cell, SOFC)、質(zhì)子交換膜燃料電池(protonex change membrane fuel cell, PEMFC)、直接醇類燃料電池(direct alcohol fuel cell, DAFC)的特點(diǎn)、研究狀況、市場需求和技術(shù)挑戰(zhàn).初步探討了我國燃料電池研究開發(fā)的前景.
關(guān)鍵詞:燃料電池;能源;能量轉(zhuǎn)換效率
來源出版物:物理,2004, 33(2): 79-84
被引頻次:129
中國燃料電池的發(fā)展
畢道治
摘要:中國燃料電池的研究始于1958年.回顧了中國燃料電池40年的發(fā)展歷程并簡介了近期(1998年1月—2000年12月)燃料電池發(fā)展計(jì)劃.概述了70年代中國燃料電池開發(fā)高潮時(shí)期在空間用堿性氫氧燃料電池開發(fā)中所取得的主要成果及各種地面用堿性燃料電池包括氨空氣電池;肼空氣電池及乙二醇空氣電池等的研究開發(fā)情況.介紹了進(jìn)入90年代以來中國在質(zhì)子交換膜燃料電池、熔融碳酸鹽燃料電池及固體氧化物燃料電池等領(lǐng)域的最新研究開發(fā)狀況,并結(jié)合中國的能源資源狀況及城市大氣污染等問題對中國燃料電池的開發(fā)應(yīng)用前景進(jìn)行了討論.
關(guān)鍵詞:燃料電池;堿性氫氧燃料電池;質(zhì)子交換膜燃料電池;熔融碳酸鹽燃料電池;固體氧化物燃料電池
來源出版物:電源技術(shù),2000, 24(2): 103-107
被引頻次:107
我國燃料電池發(fā)展概況
陸天虹,孫公權(quán)
摘要:燃料電池研究與開發(fā)的原因主要在于其質(zhì)量輕、體積小、能量轉(zhuǎn)換效率高等.本文綜述了我國燃料電池的發(fā)展概況.依燃料電池所用電解質(zhì)的類型,分別討論了堿性燃料電池、質(zhì)子交換膜燃料電池、熔融碳酸鹽燃料電池和固體氧化物燃料電池在我國的研究、開發(fā)與進(jìn)展?fàn)顩r,并與國外燃料電池近年來的研究水平作了簡單的比較.
關(guān)鍵詞:堿性燃料電池;質(zhì)子交換膜燃料電池;熔融碳酸鹽燃料電池;固體氧化物燃料電池
來源出版物:電源技術(shù),1998, 22(4): 182-184
被引頻次:102
燃料電池技術(shù)的發(fā)展與我國應(yīng)有的對策
查全性
摘要:本文介紹了幾種主要類型燃料電池的最新進(jìn)展,基于世界發(fā)展趨勢和我國具體情況,作者在堿性燃料電池、磷酸型燃料電池、熔融碳酸鹽電池和聚合物電解質(zhì)燃料電池方面提出了相應(yīng)對策,以促進(jìn)我國燃料電池的研究與開發(fā).
關(guān)鍵詞:燃料電池;堿性燃料電池;磷酸燃料電池;熔融碳酸鹽燃料電池;聚合物電解質(zhì)燃料電池
來源出版物:應(yīng)用化學(xué),1993, 10(5): 38-42
被引頻次:95
燃料電池——有前途的分布式發(fā)電技術(shù)
張穎穎,曹廣益,朱新堅(jiān)
摘要:在現(xiàn)代發(fā)電系統(tǒng)中,分布式發(fā)電技術(shù)日益成為傳統(tǒng)大電網(wǎng)的有力補(bǔ)充.文章簡要介紹了分布式發(fā)電的優(yōu)勢、種類及其各自的特點(diǎn),以及各種分布式發(fā)電技術(shù)的市場發(fā)展趨勢,詳細(xì)分析了各種燃料電池在分布式發(fā)電市場中的應(yīng)用現(xiàn)狀,對燃料電池在分布式發(fā)電市場中的應(yīng)用前景進(jìn)行了展望,并結(jié)合中國國情指出了我國有條件并且應(yīng)該加快發(fā)展燃料電池分布式發(fā)電技術(shù).
關(guān)鍵詞:大電網(wǎng);分布式發(fā)電;燃料電池;商業(yè)化;電力體制改革;可持續(xù)發(fā)展
來源出版物:電網(wǎng)技術(shù),2005, 29(2): 57-61
被引頻次:91
固體氧化物燃料電池
彭蘇萍,韓敏芳,楊翠柏,等
摘要:高效、潔凈、全固態(tài)結(jié)構(gòu)、高溫運(yùn)行的固體氧化物燃料電池(SOFC)是把反應(yīng)物的化學(xué)能直接轉(zhuǎn)化為電能的電化學(xué)裝置,這種新型發(fā)電技術(shù)是目前發(fā)展最快的能源技術(shù)之一,有望在近年內(nèi)走向商業(yè)化應(yīng)用.SOFC單體電池由致密的電解質(zhì)和多孔的陽極、陰極組成,現(xiàn)在主要發(fā)展了管狀結(jié)構(gòu)和平板式結(jié)構(gòu)兩種形式.單體電池通過致密的連接體材料以各種方式組裝成電池組,廣泛應(yīng)用于大型發(fā)電廠、熱電耦合設(shè)備、小型供能系統(tǒng)和交通工具等,市場前景廣闊.
關(guān)鍵詞:固體氧化物燃料電池(SOFC);新型能源
來源出版物:物理,2004, 33(2): 90-94
被引頻次:91
中溫固體氧化物燃料電池電解質(zhì)材料的研究進(jìn)展
魏麗,陳誦英,王琴
摘要:評述了中溫固體氧化物燃料電池(中溫SOFC)中固體電解質(zhì)的研究進(jìn)展,對ZrO2基、CeO2基、Bi2O3基和ABO3型的鈣鈦礦類4種電解質(zhì)材料的最新進(jìn)展和今后的發(fā)展趨勢作了評述.對幾種電解質(zhì)材料的優(yōu)缺點(diǎn)進(jìn)行了分析,同時(shí)對高溫電解質(zhì)YSZ薄膜化技術(shù)也作了簡要介紹,因此不難得出,尋求新的、優(yōu)良的中溫SOFC的電解質(zhì)材料仍然是新世紀(jì)推動(dòng)中溫SOFC實(shí)用化的關(guān)鍵任務(wù)之一,而YSZ薄膜化技術(shù)的研究則是研究的另一個(gè)重點(diǎn),且最有可能取得突破.
關(guān)鍵詞:材料科學(xué);中溫SOFC;電解質(zhì)材料;電導(dǎo)率;YSZ薄膜
來源出版物:稀有金屬,2003, 27(2): 286-292
被引頻次:85
燃料電池電動(dòng)汽車的技術(shù)難關(guān)和發(fā)展前景
陳全世,齊占寧
摘要:本文在闡述了質(zhì)子交換膜燃料電池上作原理的基礎(chǔ)上,首先介紹了其質(zhì)子交換膜與催化劑的研究現(xiàn)狀.然后針對汽車領(lǐng)域的需要,給出了燃料電池發(fā)動(dòng)機(jī)的概念,并對其燃料和氧化劑供給、水/熱管理和控制等各子系統(tǒng)所要解決的技術(shù)難關(guān)進(jìn)行了系統(tǒng)分析.同時(shí)對燃料電池車商業(yè)化所必然要涉及的氫燃料供給和價(jià)格等問題進(jìn)行了較客觀的論述.最后對燃料電池車的發(fā)展前景進(jìn)行了預(yù)測,提出了相應(yīng)的發(fā)展措施.
關(guān)鍵詞:質(zhì)子交換膜燃料電池;電動(dòng)汽車;技術(shù)難關(guān);前景
來源出版物:汽車工程,2001, 23(6): 361-364
被引頻次:2406
Materials for fuel-cell technologies
Steele, BCH; Heinzel, A
Abstract: Fuel cells convert chemical energy directly into electrical energy with high efficiency and low emission of pollutants. However,before fuel-cell technology can gain a significant share of the electrical power market, important issues have to be addressed. These issues include optimal choice of fuel, and the development of alternative materials in the fuel-cell stack. Present fuel-cell prototypes often use materials selected more than 25 years ago. Commercialization aspects, including cost and durability, have revealed inadequacies in some of these materials. Here we summarize recent progress in the search and development of innovative alternative materials.
Keywords: polymer electrolyte; stainless-steel; bipolar plates; 500-degrees-c; operation
來源出版物:Nature, 2001, 414(6861): 345-352
被引頻次:1674
On the development of proton conducting polymer membranes for hydrogen and methanol fuel cells
Kreuer, KD
Abstract: The transport properties and the swelling behaviour of NAFION and different sulfonated polyetherketones are explained in terms of distinct differences on the microstructures and in the pK(a)of the acidic functional groups. The less pronounced hydrophobic/hydrophilic separation of sulfonated polyetherketones compared to NAFION corresponds to narrower, less connected hydrophilic channels and to larger separations between less acidic sulfonic acid functional groups. At high water contents, this is shown to significantly reduce electroosmotic drag and water permeation whilst maintaining high proton conductivity. Blending of sulfonated polyetherketones with other polyaryls even further reduces the solvent permeation (a factor of 20 compared to NAFION), increases the membrane flexibility in the dry state and leads to an improved swelling behaviour. Therefore, polymers based on sulfonated polyetherketones are not only interesting low-cost alternative membrane material for hydrogen fuel cell applications, they may also help to reduce the problems associated with high water drag and high methanol cross-over in direct liquid methanol fuel cells (DMFC). The relatively high conductivities observed for oligomers containing imidazole as functional groups may be exploited in fully polymeric proton conducting systems with no volatile proton solvent operating at temperatures significantly beyond 100 degrees C, where methanol vapour may be used as a fuel in DMFCs.
Keywords: NAFION; polymer membrane; direct liquid methanol fuel cell; proton conductivity; electroosmotic drag; permeation; proton diffusion
來源出版物:Journal of Membrane Science, 2001, 185(1): 29-39
被引頻次:1656
Polymer Electrolyte Fuel-Cell Model
Springer, TE
Abstract: 參見本期“經(jīng)典文獻(xiàn)推薦”欄目.
被引頻次:1332
A high-performance cathode for the next generation of solid-oxide fuel cells
Shao, ZP; Haile, SM
Abstract: Fuel cells directly and efficiently convert chemical energy to electrical energy (1). Of the various fuel cell types, solid-oxide fuel cells (SOFCs)combine the benefits of environmentally benign power generation with fuel flexibility. However, the necessity for high operating temperatures (800-1000 degrees C)has resulted in high costs and materials compatibility challenges (2). As a consequence,significant effort has been devoted to the development of intermediate-temperature (500-700 degrees C)SOFCs. A key obstacle to reduced-temperature operation of SOFCs is the poor activity of traditional cathode materials for electrochemical reduction of oxygen in this temperature regime (2). Here we present Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF)as a new cathode material for reduced-temperature SOFCoperation. BSCF, incorporated into a thin-film doped ceria fuel cell, exhibits high power densities (1010 mW cm-2and 402 mW cm-2at 600 degrees C and 500 degrees C, respectively)when operated with humidified hydrogen as the fuel and air as the cathode gas. We further demonstrate that BSCF is ideally suited to ‘single-chamber’ fuel-cell operation, where anode and cathode reactions take place within the same physical chamber (3). The high power output of BSCF cathodes results from the high rate of oxygen diffusion through the material. By enabling operation at reduced temperatures, BSCF cathodes may result in widespread practical implementation of SOFCs.
Keywords: oxygen permeation; membranes; electrolyte; stability
來源出版物:Nature, 2004, 431(7005): 170-173
被引頻次:1034
Nitrogen-Doped Graphene as Efficient Metal-Free Electrocatalyst for Oxygen Reduction in Fuel Cells
Qu, Liangti; Liu, Yong; Baek, Jong-Beom
Abstract: Nitrogen-doped graphene (N-graphene)was synthesized by chemical vapor deposition of methane in the presence of ammonia. The resultant N-graphene was demonstrated to act as a metal-free electrode with a much better electrocatalytic activity, long-term operation stability, and tolerance to crossover effect than platinum for oxygen reduction via a four-electron pathway in alkaline fuel cells. To the best of our knowledge, this is the first report on the use of graphene and its derivatives as metal-free catalysts for oxygen reduction. The important role of N-doping to oxygen reduction reaction (ORR)can be applied to various carbon materials for the development of other metal-free efficient ORR catalysts for fuel cell applications, even new catalytic materials for applications beyond fuel cells.
Keywords: graphene; N-doping; oxygen reduction; fuel cell
來源出版物:ACS Nano, 2010, 4(3): 1321-1326
被引頻次:1023
Origin of the over potential for oxygen reduction at a fuel-cell cathode
Norskov, JK; Rossmeisl, J; Logadottir, A; et al.
Abstract: We present a method for calculating the stability of reaction intermediates of electrochemical processes on the basis of electronic structure calculations. We used that method in combination with detailed density functional calculations to develop a detailed description of the free-energy landscape of the electrochemical oxygen reduction reaction over Pt (111)as a function of applied bias. This allowed us to identify the origin of the over potential found for this reaction. Adsorbed oxygen and hydroxyl are found to be very stable intermediates at potentials close to equilibrium, and the calculated rate constant for the activated proton/electron transfer to adsorbed oxygen or hydroxyl can account quantitatively for the observed kinetics. On the basis of a database of calculated oxygen and hydroxyl adsorption energies, the trends in the oxygen reduction rate for a large number of different transition and noble metals can be accounted for. Alternative reaction mechanisms involving proton/electron transfer to adsorbed molecular oxygen were also considered, and this peroxide mechanism was found to dominate for the most noble metals. The model suggests ways to improve the electrocatalytic properties of fuel-cell cathodes.
Keywords: total-energy calculations; alloy surfaces; electrocatalysis; kinetics; CO; oxidation; platinum; temperature; electrodes;adsorption
來源出版物:Journal of Physical Chemistry B, 2004, 108(46): 17886-17892
被引頻次:940
Direct oxidation of hydrocarbons in a solid-oxide fuel cell
Park, SD; Vohs, JM; Gorte, RJ
Abstract: The direct electrochemical oxidation of dry hydrocarbon fuels to generate electrical power has the potential to accelerate substantially the use of fuel cells in transportation and distributed-power applications (1). Most fuel-cell research has involved the use of hydrogen as the fuel, although the practical generation and storage of hydrogen remains an important technological hurdle (2). Methane has been successfully oxidized electrochemically (3-6), but the susceptibility to carbon formation from other hydrocarbons that may be present or poor power densities have prevented the application of this simple fuel in practical applications (1). Here we report the direct,electrochemical oxidation of various hydrocarbons (methane, ethane, 1-butene, n-butane and toluene)using a solid-oxide fuel cell at 973 and 1073 K with a composite anode of copper and ceria (or samaria-doped ceria). We demonstrate that the final products of the oxidation are CO2and water, and that reasonable power densities can be achieved. The observation that a solid-oxide fuel cell can be operated on dry hydrocarbons, including liquid fuels, without reforming suggests that this type of fuel cell could provide an alternative to hydrogen-based fuel-cell technologies.
來源出版物:Nature, 2000, 404(6775): 265-267
被引頻次:875
A Mathematical-Model of the Solid-Polymer-Electrolyte Fuel-Cell
Bernardi, DM; Verbrugge, MW
Abstract: 參見本期“經(jīng)典文獻(xiàn)推薦”欄目.
被引頻次:827
Iron-Based Catalysts with Improved Oxygen Reduction Activity in Polymer Electrolyte Fuel Cells
Lefevre, Michel; Proietti, Eric; Jaouen, Frederic; et al.
Abstract: Iron-based catalysts for the oxygen-reduction reaction in polymer electrolyte membrane fuel cells have been poorly competitive with platinum catalysts, in part because they have a comparatively low number of active sites per unit volume. We produced microporous carbon-supported iron-based catalysts with active sites believed to contain iron cations coordinated by pyridinic nitrogen functionalities in the interstices of graphitic sheets within the micropores. We found that the greatest increase in site density was obtained when a mixture of carbon support, phenanthroline, and ferrous acetate was ball-milled and then pyrolyzed twice, first in argon, then in ammonia. The current density of a cathode made with the best iron-based electrocatalyst reported here can equal that of a platinum-based cathode with a loading of 0.4 milligram of platinum per square centimeter at a cell voltage of >=0.9 volt.
Keywords: heat-treatment affect; cathode catalyst; nonnoble electrocatalysts; sputter-deposition; Fe/N/C catalysts; O-2 reduction;carbon-blacks; site; ORR; electroreduction
來源出版物:Science, 2009, 324(5923): 71-74
被引頻次:815
A class of non-precious metal composite catalysts for fuel cells
Bashyam, Rajesh; Zelenay, Piotr
Abstract: Fuel cells, as devices for direct conversion of the chemical energy of a fuel into electricity by electrochemical reactions, are among the key enabling technologies for the transition to a hydrogen-based economy (1-3). Of several different types of fuel cells under development today, polymer electrolyte fuel cells (PEFCs)have been recognized as a potential future power source for zero-emission vehicles (4, 5). However, to become commercially viable, PEFCs have to overcome the barrier of high catalyst cost caused by the exclusive use of platinum and platinum-based catalysts (6-8)in the fuel-cell electrodes. Here we demonstrate a new class of low-cost (non-precious metal)/(heteroatomic polymer)nanocomposite catalysts for the PEFC cathode, capable of combining high oxygen-reduction activity with good performance durability. Without any optimization, the cobalt-polypyrrole composite catalyst enables power densities of about 0.15 W cm-2in H-2-O-2 fuel cells and displays no signs of performance degradation for more than 100 hours. The results of this study show that heteroatomic polymers can be used not only to stabilize the non-precious metal in the acidic environment of the PEFC cathode but also to generate active sites for oxygen reduction reaction.
Keywords: Fe-based catalysts; oxygen reduction; platinum monolayer; O-2 reduction; carbon-black; electrocatalysts; cathode; polypyrrole;proton; energy
來源出版物:Nature, 2006, 443(7107): 63-66
·推薦論文摘要·
低溫固體氧化物燃料電池電解質(zhì)材料
韓達(dá),吳天植,辛顯雙,等
摘要:低溫化是固體氧化物燃料電池(SOFC)發(fā)電技術(shù)的重要發(fā)展趨勢.SOFC工作溫度的降低不僅可極大地降低材料及制備成本,更重要的是可極大地提高其長期運(yùn)行的穩(wěn)定性.電解質(zhì)是SOFC的核心部件,可以采用電解質(zhì)薄膜化或新型電解質(zhì)材料來降低SOFC的工作溫度.本文概述了目前被廣泛研究的低溫SOFC的電解質(zhì)材料,并從其結(jié)構(gòu)及性能出發(fā),重點(diǎn)闡述了它們各自的優(yōu)點(diǎn)和局限性.
關(guān)鍵詞:低溫SOFC;新型電解質(zhì);離子電導(dǎo)率
來源出版物:中國工程科學(xué),2013, 15(2): 66-71聯(lián)系郵箱:占忠亮,zzhan@mail.sic.ac.cn
吡啶摻雜碳載鈷酞菁催化氧還原的電化學(xué)性能及在燃料電池中的應(yīng)用
戴先逢,鄭明富,徐攀,等
摘要:以碳黑(VulcanXC-72R)為載體,吡啶(Py)和鈷酞菁(CoPc)為催化劑前驅(qū)體,經(jīng)溶劑分散法制備了Py摻雜碳負(fù)載納米鈷酞菁復(fù)合催化劑(Py-CoPc/C).通過掃描電鏡-能譜分析(SEM-EDS)、X射線光電子能譜(XPS)分析和X射線衍射(XRD)分析技術(shù)對催化劑的組成和微觀結(jié)構(gòu)進(jìn)行了表征,并運(yùn)用線性掃描循環(huán)伏安法(LSV)和旋轉(zhuǎn)圓盤電極(RDE)技術(shù)考察了不同Py摻雜含量對碳載鈷酞菁(CoPc/C)催化氧還原反應(yīng)(ORR)活性的影響及穩(wěn)定性.結(jié)果顯示:Py摻雜可以明顯改善CoPc/C對ORR的電催化性能,其中摻雜20%Py下所制備的20%Py-20%CoPc/C催化劑對ORR表現(xiàn)出最佳的催化活性,以其制備的氣體擴(kuò)散電極在O2氣氛飽和的0.1 mol·L-1KOH電解質(zhì)溶液中,0.2 V(相對于標(biāo)準(zhǔn)氫電極)即可產(chǎn)生明顯的氧還原電流,半波電位為-0.03 V.相比于40%Py/C和未摻雜的40%CoPc/C,20%Py-20%CoPc/C催化劑的半波電位分別正移了160和15 mV.進(jìn)一步運(yùn)用RDE理論研究表明,在Py-CoPc/C電極上ORR的電子轉(zhuǎn)移總數(shù)為2.38,高于CoPc/C電極上的電子轉(zhuǎn)移總數(shù)1.96,從而使ORR的選擇性明顯提高.SEM-EDS和XRD分析表明Py摻雜提高了CoPc/C催化劑的分散性和N含量,更利于O2的吸附.XPS分析表明:吡啶結(jié)構(gòu)的N與石墨結(jié)構(gòu)的N均存在于Py-CoPc/C催化劑中,與催化劑表面的Co離子配位可能是促使ORR活性提高的原因.最后以20%Py-20%CoPc/C制備了膜電極組裝(MEA)電極,應(yīng)用于 H2/O2燃料電池單電池發(fā)電,室溫下獲得最大發(fā)電功率密度為21 mW·cm-2,相對于CoPc/C提高至2.4倍.
關(guān)鍵詞:碳載鈷酞菁;吡啶氮摻雜;氧還原反應(yīng);膜電極組裝;H2-O2單電池
來源出版物:物理化學(xué)學(xué)報(bào),2013, 29(8): 1753-1761聯(lián)系郵箱:喬錦麗,qiaojl@dhu.edu.cn
質(zhì)子交換膜燃料電池Pt納米線電催化劑研究現(xiàn)狀
嚴(yán)澤宇,李冰,楊代軍,等
摘要:質(zhì)子交換膜燃料電池(PEMFC)能直接將化學(xué)能轉(zhuǎn)換為電能,具有能量轉(zhuǎn)換效率高、環(huán)境友好、啟動(dòng)快等優(yōu)點(diǎn).其中電催化劑是決定PEMFC性能、壽命及成本的關(guān)鍵材料之一.目前所采用的Pt催化劑成本較高,是阻礙其商業(yè)化的主要因素.而Pt納米線電催化劑的Pt利用率和催化劑活性高,抗CO毒性以及耐久性好.本文綜述了Pt納米線電催化劑的制備及其電化學(xué)催化性能的研究現(xiàn)狀.
關(guān)鍵詞:質(zhì)子交換膜燃料電池;電催化劑;鉑;納米線
來源出版物:催化學(xué)報(bào),2013, 34(8): 1471-1481聯(lián)系郵箱:李冰,libing210@#edu.cn
質(zhì)子交換膜燃料電池陰極風(fēng)扇系統(tǒng)實(shí)驗(yàn)研究
朱星光,賈秋紅,陳唐龍
摘要:對自制的陰極開放式自增濕型質(zhì)子交換膜燃料電池陰極風(fēng)扇系統(tǒng)不同工作模式下電池的空氣流量分布及溫度分布開展了實(shí)驗(yàn)研究.采用testo435多功能測量儀測量不同工作模式下電池陰極的空氣流速;采用FLUKE Ti25紅外溫度成像儀測量不同操作模式下電池的表面溫度分布.實(shí)驗(yàn)結(jié)果表明:陰極風(fēng)扇系統(tǒng)不同的工作模式(“吸”和“吹”)會(huì)造成空氣流量分布及溫度分布不同.風(fēng)扇工作在“吸”模式下,燃料電池的表面工作溫度分布和空氣流量分布更均勻,性能更好;電池表面工作溫度分布與流過電池陰極的空氣流量具有一致性.該研究對于陰極開放式燃料電池性能研究及尋求電池系統(tǒng)效率、性能、溫濕度等整體最優(yōu)具有一定的指導(dǎo)和參考價(jià)值.
關(guān)鍵詞:質(zhì)子交換膜燃料電池;陰極風(fēng)扇系統(tǒng);不同工作模式;空氣流量分布;表面工作溫度分布
來源出版物:中國電機(jī)工程學(xué)報(bào),2013, 33(11): 47-53聯(lián)系郵箱:賈秋紅,jqh.01@163.com
改性石墨烯用作燃料電池陰極催化劑
鐘軼良,莫再勇,楊莉君,等
摘要:石墨烯材料以其獨(dú)特的超薄片層結(jié)構(gòu)、超高比表面積、良好的導(dǎo)電性等重要特性,而被認(rèn)為在制備高性能燃料電池催化劑方面具有重要的潛在應(yīng)用價(jià)值.最近的一些研究工作表明,通過選擇合適的制備方法和前驅(qū)體制備的改性石墨烯,對于氧還原反應(yīng)具有一定的活性,可用作燃料電池陰極催化劑.目前有關(guān)石墨烯應(yīng)用于燃料電池陰極催化劑的研究工作主要集中在兩個(gè)方面:一是通過表面改性后直接作為燃料電池非貴金屬陰極催化劑;二是將改性石墨烯作陰極催化劑載體而制備活性組分高度分散的高性能催化劑.盡管有關(guān)改性石墨烯的氧還原活性中心的結(jié)構(gòu)尚不明確,然而由于這類材料在酸性及堿性環(huán)境下對氧還原的良好的催化性能,對改性石墨烯的研究已成為探索燃料電池非鉑催化劑的新途徑.隨著這類材料的催化性能的不斷提高和對表面-活性關(guān)系認(rèn)識的不斷深入,改性石墨烯材料在燃料電池方面將具有廣闊的應(yīng)用前景.
關(guān)鍵詞:石墨烯改性;燃料電池;氧還原反應(yīng);陰極催化劑
來源出版物:化學(xué)進(jìn)展,2013, 25(5): 717-725聯(lián)系郵箱:廖世軍,chsiliao@scut.edu.cn
新型鈷-聚吡咯-碳載Pt燃料電池催化劑的制備與表征
范仁杰,林瑞,黃真,等
摘要:采用脈沖微波輔助化學(xué)還原法制備了鈷-聚吡咯-碳(Co-PPy-C)載Pt催化劑(Pt/Co-PPy-C),其中Pt的總質(zhì)量占20%.利用透射電鏡(TEM)、光電子射線能譜分析(XPS)和X射線衍射(XRD)研究了催化劑的結(jié)構(gòu),用循環(huán)伏安(CV)、線性掃描伏安(LSV)等方法考察了其電化學(xué)活性及氧還原反應(yīng)(ORR)動(dòng)力學(xué)特性及耐久性.Pt/Co-PPy-C電催化劑的金屬顆粒直徑約1.8 nm,略小于商用催化劑Pt/C(JM)顆粒尺寸(約2.5 nm);催化劑在載體上分散均勻,粒徑分布范圍較窄.Pt/Co-PPy-C的電化學(xué)活性比表面積(ECSA)(75.1 m2·g-1)高于商用催化劑的ECSA(51.3 m2·g-1).XPS測試表明,自制催化劑表面的Pt主要以零價(jià)形式存在.而XRD結(jié)果顯示,自制催化劑中Pt(111)峰最強(qiáng),Pt主要為面心立方晶格.Pt/Co-PPy-C具有與Pt/C(JM)相同的半波電位;在0.9 V下.Pt/Co-PPy-C的比活性(1.21 mA·cm-2)高于商用催化劑的比活性(1.04 mA·cm-2),表現(xiàn)出更好的ORR催化活性.動(dòng)力學(xué)性能測試表明催化劑的ORR反應(yīng)以四電子路線進(jìn)行.CV測試1000圈后,Pt/Co-PPy-C和Pt/C(JM)的ECSA分別衰減了13.0%和24.0%,可見自制催化劑的耐久性高于商用Pt/C(JM),在質(zhì)子交換膜燃料電池(PEMFC)領(lǐng)域有一定的應(yīng)用前景.
關(guān)鍵詞:質(zhì)子交換膜燃料電池;催化劑;鈷-聚吡咯-碳;氧還原反應(yīng);微波化學(xué)還原
來源出版物:物理化學(xué)學(xué)報(bào),2014, 30(7): 1259-1266聯(lián)系郵箱:林瑞,ruilin@#edu.cn
通過濺射與退火制備的用于固體氧化物燃料電池的氧化釓摻雜氧化鈰電解質(zhì)隔層
武衛(wèi)明,劉中波,趙哲,等
摘要:采用濺射或?yàn)R射與退火相結(jié)合的方法制備了一系列氧化釓摻雜的氧化鈰(GDC)隔層,并考察了其對固體氧化燃料電池性能的影響.結(jié)果表明,200°C下濺射獲得了立方結(jié)構(gòu)氧化釓摻雜的氧化鈰均勻薄膜,在900~1100°C范圍內(nèi)的退火處理使得 GDC薄膜致密,從而有效阻止了氧化釔摻雜的氧化鋯電解質(zhì)與陰極材料之間的反應(yīng),大幅度提高了電池的電化學(xué)性能.
關(guān)鍵詞:固體氧化物燃料電池;稀土金屬氧化物;氧化釓摻雜的氧化鈰;隔層;濺射;退火
來源出版物:催化學(xué)報(bào),2014, 35(8): 1376-1384聯(lián)系郵箱:程謨杰,mjcheng@dicp.ac.cn
固體氧化物燃料電池平板式電池堆的研究進(jìn)展
宋世棟,韓敏芳,孫再洪
摘要:燃料電池可以直接將燃料的化學(xué)能轉(zhuǎn)化為電能,其發(fā)電效率高、污染物排放少,是一種高效、潔凈的發(fā)電裝置.固體氧化物燃料電池(SOFC)的燃料適用性強(qiáng)、穩(wěn)定性好,被認(rèn)為是現(xiàn)階段最有應(yīng)用前景的綠色發(fā)電系統(tǒng).本文介紹了SOFC的平板式單電池及電池堆的最新研究進(jìn)展,以及國際上代表性研發(fā)單位的技術(shù)現(xiàn)狀,并提出了在平板式SOFC商業(yè)化進(jìn)程中亟待解決的問題.
關(guān)鍵詞:固體氧化物燃料電池;電池堆;發(fā)電系統(tǒng);平板式;碳?xì)淙剂?/p>
來源出版物:科學(xué)通報(bào),2014, 59(15):1405-1416聯(lián)系郵箱:韓敏芳,hanminfang@sina.com
交流阻抗技術(shù)在質(zhì)子交換膜燃料電池上的研究進(jìn)展
蔡光旭,郭建偉,王佳
摘要:質(zhì)子交換膜燃料電池(PEMFC)具有低溫、高效、零排放等特點(diǎn),是有效解決環(huán)境污染和能源危機(jī)的發(fā)電裝置,然而其內(nèi)在電化學(xué)、傳輸機(jī)理不明確限制了其發(fā)展.交流阻抗技術(shù)(EIS)作為研究電極過程動(dòng)力學(xué)和表面現(xiàn)象的重要手段,應(yīng)用在PEMFC上受到高度重視.本文概括介紹了EIS的應(yīng)用原理以及對于PEMFC的測量方式,并重點(diǎn)結(jié)合電池電極中典型的阻抗譜解析,總結(jié)了近來EIS在電池和材料兩個(gè)方面的研究進(jìn)展,從原位極化分析、材料性能評估及反應(yīng)機(jī)理剖析等幾個(gè)方面予以深入,詳細(xì)分析了各阻抗元件參數(shù)對電池和材料改進(jìn)的指導(dǎo)作用,進(jìn)而展望了EIS在燃料電池上的應(yīng)用前景,指出除了采用等效電路加以分析以外,結(jié)合數(shù)學(xué)模型推導(dǎo)將更加完美呈現(xiàn)出阻抗譜數(shù)據(jù)的特點(diǎn).
關(guān)鍵詞:交流阻抗技術(shù);電極;材料;質(zhì)子交換膜燃料電池
來源出版物:化工進(jìn)展,2014, 33(1): 56-63聯(lián)系郵箱:郭建偉,jwguo@mail.tsinghua.edu.cn
共流延法制備固體氧化物燃料電池陽極的優(yōu)化
駱婷,史堅(jiān),王紹榮,等
摘要:采用共流延成型、共燒結(jié)法制備了以Ni-YSZ陽極支撐的氧化鈧穩(wěn)定的氧化鋯(SSZ)電解質(zhì)膜.為提高電化學(xué)活性在支撐陽極與電解質(zhì)膜之間引入了Ni-SSZ活性陽極.通過調(diào)整活性陽極的厚度和SSZ:NiO的質(zhì)量比優(yōu)化了陽極活性;通過比較支撐陽極中添加不同造孔劑含量時(shí)的性能,優(yōu)化了支撐陽極的孔隙率.研究結(jié)果表明,當(dāng)活性層厚度為35 μm,質(zhì)量比為 w(SSZ):w(NiO)=1:1,支撐層造孔劑含量為10 wt%時(shí),陽極活性最佳;采用絲網(wǎng)印刷并燒結(jié)LSM-SSZ復(fù)合陰極后,所得單電池在750℃的最高功率密度達(dá)到0.96 W/cm2,比優(yōu)化前本課題組前期報(bào)道的性能提高了2.3倍.
關(guān)鍵詞:固體氧化物燃料電池;活性層;優(yōu)化;流延法
來源出版物:無機(jī)材料學(xué)報(bào),2014, 29(2): 203-208聯(lián)系郵箱:王紹榮,srwang@mail.sic.ac.cn
碳材料的摻雜改性及其用于燃料電池催化劑的研究
鄭銳萍,廖世軍
摘要:開發(fā)摻雜改性的碳材料用作燃料電池的非貴金屬氧還原催化劑已成為燃料電池領(lǐng)域的重要研究課題,相關(guān)研究對于降低燃料電池成本、促進(jìn)燃料電池的商業(yè)化具有十分重要的意義.大量研究工作表明,對碳材料進(jìn)行摻雜改性可以實(shí)現(xiàn)其形貌、微觀結(jié)構(gòu)、組成及其他表面物理化學(xué)性質(zhì)的優(yōu)化,從而得到具有較高催化活性、選擇性和穩(wěn)定性的氧還原催化劑.人們在這類催化劑的制備方法、性能優(yōu)化和催化機(jī)理等方面進(jìn)行了大量研究工作.綜述了對碳納米管、石墨烯、介孔碳、大孔碳、碳微球等碳材料進(jìn)行摻雜改性的最新進(jìn)展.并基于目前的研究結(jié)果,展望了摻雜碳材料作為燃料電池非貴金屬氧還原催化劑的應(yīng)用前景和未來的發(fā)展趨勢.
關(guān)鍵詞:摻雜;改性;碳材料;催化劑;燃料電池
來源出版物:表面技術(shù),2015, 44(1): 34-40
以木片氣為燃料的中溫型固體氧化物燃料電池/燃?xì)廨啓C(jī)混合動(dòng)力系統(tǒng)性能研究
呂小靜,耿孝儒,朱新堅(jiān),等
摘要:以木片氣化氣為燃料,建立中溫型固體氧化物燃料電池(intermediate temperature solid oxide fuel cell, IT-SOFC)/燃?xì)廨啓C(jī)(gas turbine, GT)混合動(dòng)力系統(tǒng)的詳細(xì)模型,分析混合動(dòng)力系統(tǒng)的運(yùn)行性能,研究生物質(zhì)氣的組分和水碳比的變化對混合動(dòng)力系統(tǒng)性能的影響.結(jié)果表明,在設(shè)計(jì)工況下,以木片氣化氣為燃料的IT-SOFC/GT混合動(dòng)力系統(tǒng)的發(fā)電效率高達(dá)59.24%,具有較好的系統(tǒng)性能.生物質(zhì)氣組分的變化對混合動(dòng)力系統(tǒng)性能影響很大,H2百分比的變化使系統(tǒng)輸出功率變化幅度最大,CO和 CH4相近,系統(tǒng)的發(fā)電效率隨H2百分比增加略有上升,隨CO和CH4百分比的增加下降明顯.研究還表明,當(dāng)水碳摩爾比([S]/[C])改變時(shí),系統(tǒng)輸出功率和發(fā)電效率隨著[S]/[C]的減小而逐漸增加,但從系統(tǒng)運(yùn)行安全性和壽命方面考慮,應(yīng)選擇適當(dāng)?shù)模跾]/[C]值.
關(guān)鍵詞:中溫型固體氧化物燃料電池;燃?xì)廨啓C(jī);混合動(dòng)力系統(tǒng);生物質(zhì)氣;組分變化;水碳比變化
來源出版物:中國電機(jī)工程學(xué)報(bào),2015, 35(1): 133-141
直接碳燃料電池燃料的研究進(jìn)展
劉國陽,張亞婷,蔡江濤,等
摘要:直接碳燃料電池(DCFC)具有能量轉(zhuǎn)化效率高、污染低、燃料來源廣等優(yōu)點(diǎn),是緩解能源危機(jī)和環(huán)境污染的一種有效途徑,其性能與所使用的燃料密切相關(guān).本文介紹DCFC的發(fā)展歷史、研究現(xiàn)狀及發(fā)展動(dòng)態(tài),評述了煤、焦炭、活性炭、石墨等含碳物質(zhì)作為DCFC燃料的優(yōu)缺點(diǎn),分析討論了碳燃料的晶體結(jié)構(gòu)缺陷、表面含氧官能團(tuán)對陽極電化學(xué)反應(yīng)的促進(jìn)作用,以及碳燃料的電解質(zhì)潤濕能力、孔隙結(jié)構(gòu)、電導(dǎo)率、粒徑大小對陽極電化學(xué)反應(yīng)的質(zhì)量傳遞與電荷傳遞的相互關(guān)系;探討了陽極催化劑促進(jìn)陽極反應(yīng)并提高電池性能的機(jī)制;簡要討論了DCFC碳燃料的未來發(fā)展趨勢.
關(guān)鍵詞:直接碳燃料電池;燃料;煤;發(fā)展趨勢
來源出版物:新型炭材料,2015, 30(1): 12-18聯(lián)系郵箱:邱介山,jqiu@ dlut.edu.cn
質(zhì)子交換膜燃料電池電源系統(tǒng)停機(jī)特性及控制策略
彭躍進(jìn),彭赟,李倫,等
摘要:質(zhì)子交換膜燃料電池(PEMFC)電源系統(tǒng)在停機(jī)后,燃料電池開路高電壓被認(rèn)為是造成電池性能下降和壽命縮短的重要因素.這主要是因?yàn)镻EMFC電源系統(tǒng)停機(jī)后,燃料電池處于開路狀態(tài),陽極側(cè)殘留的氫氣和陰極側(cè)的空氣發(fā)生電化學(xué)反應(yīng),電池電壓為開路高電壓且維持在開路電壓的時(shí)間比較長,這容易引起催化劑碳載體發(fā)生氧化,使分布在載體上的鉑(Pt)顆粒脫落,造成燃料電池性能衰減以及壽命縮短.以最大程度縮短停機(jī)后開路高電壓的時(shí)間和加快陽極側(cè)殘留氫氣的消耗速度為目標(biāo),提出了一種PEMFC電源系統(tǒng)的停機(jī)策略,通過實(shí)驗(yàn)分別研究了直接停機(jī)和停機(jī)策略停機(jī)對PEMFC輸出特性的影響.以該停機(jī)控制策略為基礎(chǔ),通過實(shí)驗(yàn)驗(yàn)證了該停機(jī)策略的有效性,為提出保護(hù)性的PEMFC電源系統(tǒng)停機(jī)控制策略提供了參考性指導(dǎo).
關(guān)鍵詞:質(zhì)子交換膜燃料電池;氧化;碳載體;腐蝕;停機(jī)策略
來源出版物:化工學(xué)報(bào),2015, 66(3): 1178-1184聯(lián)系郵箱:劉志祥,liuzhixiang@swjtu.edu.cn
車用質(zhì)子交換膜燃料電池材料部件
王誠,王樹博,張劍波,等
摘要:車用燃料電池主要包括質(zhì)子交換膜燃料電池、金屬-空氣燃料電池等,其中質(zhì)子交換膜燃料電池是目前車用燃料電池的主要開發(fā)對象(以下簡稱車用燃料電池).經(jīng)過全球范圍內(nèi)近十年的持續(xù)研發(fā),車用燃料電池在能量效率、功率密度與比功率、低溫啟動(dòng)等功能特性方面已經(jīng)取得了突破性進(jìn)展,新一輪的燃料電池汽車產(chǎn)業(yè)化浪潮正在迫近.然而,車用燃料電池的耐久性和成本還沒達(dá)到預(yù)期商業(yè)化目標(biāo),是其產(chǎn)業(yè)化的最后障礙.探索和研發(fā)燃料電池用新型關(guān)鍵材料部件是解決這兩大問題、推進(jìn)其商業(yè)化進(jìn)程的關(guān)鍵所在,也是車用燃料電池長期的研究重點(diǎn)和熱點(diǎn).本文系統(tǒng)地梳理了近幾年來車用燃料電池質(zhì)子交換膜、催化層、氣體擴(kuò)散層、雙板板關(guān)鍵材料部件的研究進(jìn)展和成果,并分類進(jìn)行了簡要評述,分析了其性能與商業(yè)化目標(biāo)的差距.最后展望了車用燃料電池關(guān)鍵材料部件今后的發(fā)展方向.
關(guān)鍵詞:氫能;燃料電池汽車;催化劑;質(zhì)子交換膜;擴(kuò)散層;雙極板
來源出版物:化學(xué)進(jìn)展,2015, 37(2/3): 310-320聯(lián)系郵箱:王誠,wangcheng@tsinghua.edu.cn
Electrocatalyst approaches and challenges for automotive fuel cells
Mark K. Debe
Abstract: Fuel cells powered by hydrogen from secure and renewable sources are the ideal solution for non-polluting vehicles, and extensive research and development on all aspects of this technology over the past fifteen years has delivered prototype cars with impressive performances. But taking the step towards successful commercialization requires oxygen reduction electrocatalysts-crucial components at the heart of fuel cells-that meet exacting performance targets. In addition, these catalyst systems will need to be highly durable,fault-tolerant and amenable to high-volume production with high yields and exceptional quality. Not all the catalyst approaches currently being pursued will meet those demands.
來源出版物:Nature, 2012, 486: 43-51聯(lián)系郵箱:M. K. Debe; mkdebe1@mmm.com
High temperature (HT)polymer electrolyte membrane fuel cells (PEMFC)-A review
Chandan, Amrit; Hattenberger, Mariska; El-Kharouf, Ahmad; et al.
Abstract: One possible solution of combating issues posed by climate change is the use of the High Temperature (HT)Polymer ElectrolyteMembrane (PEM)Fuel Cell (FC)in some applications. The typical HT-PEMFC operating temperatures are in the range of 100-200 degrees C which allows for co-generation of heat and power, high tolerance to fuel impurities and simpler system design. This paper reviews the current literature concerning the HT-PEMFC, ranging from cell materials to stack and stack testing. Only acid doped PBI membranes meet the US DOE (Department of Energy)targets for high temperature membranes operating under no humidification on both anode and cathode sides (barring the durability). This eliminates the stringent requirement for humidity however, they have many potential drawbacks including increased degradation, leaching of acid and incompatibility with current state-of-the-art fuel cell materials. In this type of fuel cell, the choice of membrane material determines the other fuel cell component material composition, for example when using an acid doped system,the flow field plate material must be carefully selected to take into account the advanced degradation. Novel research is required in all aspects of the fuel cell components in order to ensure that they meet stringent durability requirements for mobile applications.
Keywords: Fuel cell; Intermediate/high temperature PEM; Stack; Bipolar plate; Catalyst layer; Gas diffusion layer
來源出版物:Journal of Power Sources, 2013, 231: 264-278聯(lián)系郵箱:Bujalski, W; w.bujalski@bham.ac.uk
Recent progress in doped carbon nanomaterials as effective cathode catalysts for fuel cell oxygen reduction reaction
Yang, Zhi; Nie, Huagui; Chen, Xi’an; et al.
Abstract: The fuel cell (FC), as a clean and high-efficiency device, has drawn a great deal of attention in terms of both fundamentals and applications. However, the high cost and scarcity of the requisite platinum catalyst as well as a sluggish oxygen reduction reaction (ORR)at the cathode in FC have become the greatest barrier to large-scale industrial application of FC. The development of novel non-precious metal catalysts (NPMC)with excellent electrocatalytic performance has been viewed as an important strategy to promote the development of FC. Recent studies have proven that metal free carbon materials doped with heteroatom (e.g. N, B, P, S or Se)have also shown striking electrocatalytic performance for ORR and become an important category of potential candidates for replacing Pt-based catalysts. This review summarizes recent achievements in heteroatom doped carbon materials as ORR catalysts, and will be beneficial to future development of other novel low-cost NPMCs with high activities and long lifetimes for practical FC applications.
Keywords: Doping; Oxygen reduction; Fuel cell; Graphene; Carbon nanotubes
來源出版物:Journal of Power Sources, 2013, 236: 238-249聯(lián)系郵箱:Yang, Zhi; yang201079@126.com
PdAg Nanorings Supported on Graphene Nanosheets: Highly Methanol-Tolerant Cathode Electrocatalyst for Alkaline Fuel Cells
Liu, Minmin; Lu, Yizhong; Chen, Wei
Abstract: Due to the high costs, slow reaction kinetics, and methanol poisoning of platinum-based cathode catalysts, designing and exploring non-Pt or low-Pt cathode electrocatalysts with a low cost, high catalytic performance, and high methanol-tolerance are crucial for the commercialization of fuel cells. Here, a facile method to fabricate a system of PdAg nanorings supported by graphene nanosheets is demonstrated; the fabrication is based on the galvanic displacement reaction between pre-synthesized Ag nanoparticles and palladium ions. X-ray diffraction and high-resolution transmission electron microscopy show that the synthesized PdAg nanocrystals exhibit a ring-shaped hollow structure with an average size of 27.49 nm and a wall thickness of 5.5 nm. Compared to the commercial PdC catalyst, the PdAg nanorings exhibit superior properties as a cathode electrocatalyst for oxygen reduction. Based on structural and electrochemical studies,these advantageous properties include efficient usage of noble metals and a high surface area because of the effective utilization of both the exterior and interior surfaces, high electrocatalytic performance for oxygen reduction from the synergistic effect of the alloyed PdAg crystalline phase, and most importantly, excellent tolerance of methanol crossover at high concentrations. It is anticipated that this synthesis of graphene-based PdAg nanorings will open up a new avenue for designing advanced electrocatalysts that are low in cost and that exhibit high catalytic performance for alkaline fuel cells.
Keywords: nanorings; palladium; oxygen reduction reaction; electrocatalysts; fuel cells
來源出版物:Advanced Functional Materials, 2013, 23(10): 1289-1296聯(lián)系郵箱:Liu, Minmin; weichen@ciac.jl.cn
Alkaline polymer electrolyte membranes for fuel cell applications
Wang, Yan-Jie; Qiao, Jinli; Baker, Rya; et al.
Abstract: In this review, we examine the most recent progress and research trends in the area of alkaline polymer electrolyte membrane(PEM)development in terms of material selection, synthesis, characterization, and theoretical approach, as well as their fabrication into alkaline PEM- based membrane electrode assemblies (MEAs)and the corresponding performance/durability in alkaline polymer electrolyte membrane fuel cells (PEMFCs). Respective advantages and challenges are also reviewed. To overcome challenges hindering alkaline PEM technology advancement and commercialization, several research directions are then proposed.
Keywords: anion-exchange membranes; quaternized poly(vinyl alcohol); cross-linking; conducting membranes; transport-properties; oxy-gen reduction; performance; stability; hydroxide; radiation
來源出版物:Chemical Society Reviews, 2013, 42(13): 5768-5787聯(lián)系郵箱:Qiao, JL; qiaojl@dhu.edu.cn
Engineering Interface and Surface of Noble Metal Nanoparticle Nanotubes toward Enhanced Catalytic Activity for Fuel Cell Applications
Cui, Chun-Hua; Yu, Shu-Hong
Abstract: In order for fuel cells to have commercial viability as alternative fuel sources, researchers need to develop highly active and robust fuel cell electrocatalysts. In recent years, the focus has been on the design and synthesis of novel catalytic materials with controlled interface and surface structures. Another goal is to uncover potential catalytic activity and selectivity, as well as understand their fundamental catalytic mechanisms. Scientists have achieved great progress in the experimental and theoretical investigation due to the urgent demand for broad commercialization of fuel cells in automotive applications. However, there are still three main problems: cost, performance, and stability. To meet these targets, the catalyst needs to have multisynergic functions. In addition, the composition and structure changes of the catalysts during the reactions still need to be explored.
Activity in catalytic nanomaterials is generally controlled by the size, shape, composition, and interface and surface engineering. As such,one-dimensional nanostructures such as nanowires and nanotubes are of special interest However, these structures tend to lose the nanoparticle morphology and inhibit the use of catalysts in both fuel cell anodes and cathodes. In 2003, Rubinstein and co-workers proposed the idea of nanoparticle nanotubes (NNs), which combine the geometry of nanotubes and the morphology of nanoparticles. This concept gives both the high surface-to-volume ratio and the size effect, which are both appealing in electrocatalyst design.
In this Account, we describe our developments in the construction of highly active NNs with unique surface and heterogeneous interface structures. We try to clarify enhanced activity and stability in catalytic systems by taking into account the activity Impact factors. We briefly introduce material structural effects on the electrocatalytic reactivity including metal oxide/metal and metal/metal interfaces, dealloyed pure Pt, and mixed Pt/Pd surfaces. In addition, we discuss the geometric structure and surface composition changes and evolutions on the activity, selectivity, and stability under fuel cell operation conditions. We expect that these nanostructured materials with particular nanostructured characteristics, physical and chemical properties, and remarkable structure changes will offer new opportunities for wide scientific communities.
Keywords: ternary Pt/Pd/Cu electrocatalyst; oxygen reduction reaction; high-aspect-ratio; atomic redistribution; tellurium nanowires; methanol oxidation; platinum; tubes; Au; design
來源出版物:Accounts of Chemical Research, 2013, 46(7): 1427-1437聯(lián)系郵箱:Yu, SH; shyu@ustc.edu.cn
A Review of Graphene-Based Nanostructural Materials for Both Catalyst Supports and Metal-Free Catalysts in PEM Fuel Cell Oxygen Reduction Reactions
Zhou, Xuejun; Qiao, Jinli; Yang, Lin; et al.
Abstract: A comprehensive overview and description of graphene-based nanomaterials explored in recent years for catalyst supports and metal-free catalysts for polymer electrolyte membrane (PEM)fuel cell oxygen reduction reactions (ORR)is presented. The catalyst material structures/morphologies, material selection, and design for synthesis, catalytic performance, catalytic mechanisms, and theoretical approaches for catalyst down-selection and catalyzed ORR mechanisms are emphasized with respect to the performance of ORR catalysts in terms of both activity and stability. When graphene-based materials, including graphene and doped graphene, are used as the supporting materials for both Pt/Pt alloy catalysts and non-precious metal catalyst, the resulting ORR catalysts can give superior catalyst activity and stability compared to those of conventional carbon-supported catalysts; when they are used as metal-free ORR catalysts, significant catalytic activity and stability are observed. The nitrogen-doped graphene materials even show superior performance compared to supported metal catalysts. Challenges including the lack of material mass production, unoptimized catalyst structure/morphology, insufficient fundamental understanding, and testing tools/protocols for performance optimization and validation are identified, and approaches to address these challenges are suggested.
Keywords: nitrogen-doped graphene; methanol electrooxidation activity; lithium-ion batteries; one-pot synthesis; electrocatalytic activity;platinum nanoparticles; alloy nanoparticles; efficient electrocatalyst; energy-conversion; carbon nanotubes
來源出版物:Advanced Energy Materials, 2014, 4(8): 1289-1295聯(lián)系郵箱:Qiao, Jinli; qiaojl@dhu.edu.cn
Numerical thermomechanical modelling of solid oxide fuel cells
Peksen, Murat
Abstract: Over the last decade, many computational models have been presented to describe the complex thermomechanical behaviour of solid oxide fuel cells. The present study elucidates a detailed literature review of the proposed numerical models, ranging from a single channel or unit layer, up to coupled 3D high-end system models. Thermomechanical modelling foundations, including material propertiesand thermomechanical stress sources in SOFCs are emphasized. Employed material models for SOFC components are highlighted. Thermomechanical modelling issues such as geometrical idealisation, initial and boundary conditions for the highly coupled fluid and solid mechanics problem, as well as numerical solutions have been discussed. Thermomechanical stress-strain formulation of the common fuel cell components is highlighted. Finally, an overview of the numerically solved thermomechanical modelling studies in solid oxide fuel cells is given. Case studies are used throughout this review to exemplify and shed light on several modelling aspects.
Keywords: CFD; FEM; Multiphysics; SOFC; Thermal stress; Thermomechanics
來源出版物:Progress in Energy and Combustion Science, 2015, 48: 1-20聯(lián)系郵箱:Peksen, Murat; m.peksen@fz-juelich.de
Accelerated Membrane Durability Testing of Heavy Duty Fuel Cells
Macauley, Natalia; Alavijeh, Alireza Sadeghi; Watson, Mark; et al.
Abstract: Regular durability testing of heavy duty fuel cell systems for transit bus application requires several thousand hours of operation,which is costly and time consuming. Alternatively, accelerated durability tests are able to generate failure modes observed in field operation in a compressed time period, by applying enhanced levels of stress. The objective of the present work is to design and validate an accelerated membrane durability test (AMDT)for heavy duty fuel cells under bus related conditions. The proposed AMDT generates bus relevant membrane failure modes in a few hundred hours, which is more than an order of magnitude faster than for regular duty cycle testing. Elevated voltage, temperature, and oxidant levels are used to accelerate membrane chemical stress, while relative humidity (RH)cycling is used to induce mechanical stress. RH cycling is found to significantly reduce membrane life-time compared to constant RH conditions. The role of a platinum band in the membrane is investigated and membranes with Pt bands demonstrate a considerable life-time extension under AMDT conditions, with minimal membrane degradation. Overall, this research serves to establish a benchmark AMDT that can rapidly and reliably evaluate membrane stability under simulated heavy duty fuel cell conditions.
Keywords: perfluorosulfonated acid ionomer; polymer electrolyte membranes; active layer degradation; steady-state operation; mechanical-properties; exchange membrane; hydroxyl radicals; pemfc; platinum; hydrogen
來源出版物:Journal of the Electrochemical Society, 2015, 162(1): 98-107聯(lián)系郵箱:Macauley, Natalia; ekjeang@sfu.ca
Enhancing Hybrid Direct Carbon Fuel Cell anode performance using Ag2O
Deleebeeck, L; Ippolito, D; Hansen, K. Kammer
Abstract: A hybrid-direct carbon fuel cell (HDCFC), consisting of a molten slurry of solid carbon black and LiK2CO3added to the anode chamber of a solid oxide fuel cell, was characterized using current-potentialpower density curves, electrochemical impedance spectroscopy,and cyclic voltammetry. Two types of experimental setups were employed in this study, an anode-supported full cell configuration (two electrodes, two atmospheres setup)and a 3-electrode electrolyte-supported half-cell setup (single atmosphere). Anode processes with and without catalystswere investigated as a function of temperature (700-800 degrees C)and anode sweep gas (N-2, 4-100% CO2in N-2-CO2). It was shown that the addition of silver based catalysts (Ag, Ag2O, Ag2CO3)into the carbon-carbonate slurry enhanced the performance of the HDCFC.
Keywords: Direct carbon fuel cell (DCFC); carbon black; silver oxide; electrochemical performance; cyclic voltammetry (CV)
來源出版物:Electrochimica Acta, 2015, 152: 222-239聯(lián)系郵箱:Deleebeeck, L; ldel@dtu.dk
編輯:衛(wèi)夏雯
We present here an isothermal, one-dimensional, steady-state model for a complete polymer electrolyte fuel cell (PEFC)with a 117 Nafion(R)membrane. In this model we employ water diffusion coefficients electro-osmotic drag coefficients, water sorption isotherms,and membrane conductivities, all measured in our laboratory as functions of membrane water content. The model predicts a net-water-per-proton flux ratio of 0.2 H2O/H+under typical operating conditions, which is much less than the measured electro-osmotic drag coefficient for a fully hydrated membrane. It also predicts an increase in membrane resistance with increased current density and demonstrates the great advantage of a thinner membrane in alleviating this resistance problem. Both of these predictions were verified experimentally under certain conditions.
loading electrodes; membranes; platinum; nafion; SPE; technology; reduction; transport
高影響力文章
典
文章題目第一作者來源出版物1Polymer Electrolyte Fuel-Cell ModelSpringer, TEJournal of the Electrochemical Society, 1991,138(8): 2334-2342 2 139(9): 2477-2491 3Two-phase flow and transport in the air cathode of proton exchange membrane fuel cellsWang, ZHJournal of Power Sources, 2001, 94(1): 40-50 A Mathematical-Model of the Bernardi, DM Journal of the Electrochemical Society, 1992,Solid-Polymer-Electrolyte Fuel-Cell 4 A Water and Heat Management Model for Nguyen, TV Journal of the Electrochemical Society, 1993,Proton-Exchange-Membrane Fuel-Cells
Polymer Electrolyte Fuel-Cell Model
Springer, TE; Zawodzinski, TA; Gottesfeld, S
*摘編自《電化學(xué)》2012年18卷1期:1~14頁