A parametric study of PEM fuel cell performances

Wang, Lin; Husar, Attila; Zhou, Tianhong; Liu, Hongtan

doi:10.1016/s0360-3199(02)00284-7

Cited by 570 publications

(211 citation statements)

References 17 publications

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“…18 Na avaliação de MEAs, são estudados potenciais desde o potencial de circuito aberto, em torno de 1 V até 0 (zero), ou um potencial considerado adequado aos dispositivos utilizados, uma vez que baixos potenciais exigem maiores densidades de corrente e que potenciais entre 0,5 e 0,7 V são utilizados nas aplicações práticas, em função da boa relação entre potência e durabilidade que proporcionam aos MEAs. A faixa de potencial utilizada na avaliação do MEA foi entre 1,0 e 0,3 V. 9,[19][20][21] Neste estudo foi formulada uma TPCC para aplicação sobre GDL, considerando os parâmetros apresentados e foi desenvolvido um processo de aplicação da TPCC por impressão a tela, permitindo o preparo de eletrodos de difusão gasosa para uso na confecção de MEAs para PEMFC.…”

Section: Introductionunclassified

Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC) por impressão a tela

Bonifácio¹,

Linardi²,

Cuenca³

2011

Quím. Nova

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. Proton exchange membrane fuel cell (PEMFC) requires membrane electrode assemblies (MEA) to generate electrical energy from hydrogen and oxygen. In this study a MEA production process by sieve printing and an ink composition were developed to produce catalyst layers of MEAs. The deposition of the exact catalyst content was possible on cathodes and anodes with only one print step. The optimal ink developed shown viscosity of 2.75 Pa s, density 1.27 g cm -3 , total solid content of 33.76 % and tack of 92 U.T. The electrodes prepared in only one printing step showed higher performance than those prepared in several steps.Keywords: membrane electrode assembly; catalytic layer; ink composition. INTRODUÇÃOA demanda mundial de energia é uma tendência historicamente crescente e irreversível, por diversos fatores, dentre eles pode-se citar o aumento da população, que vem ocorrendo a altas taxas. Segundo projeções, a população mundial deve ultrapassar 9,2 bilhões de pessoas até 2050, o que corresponde a um aumento populacional de 43% em relação a 2007. 1 Também segundo projeções, em 2080 o hidrogênio será a principal fonte de geração de energia do mundo, sendo então responsável por aproximadamente 90% da matriz energética. 2 Diante dessas projeções, o desenvolvimento de sistemas capazes de gerar energia elétrica a partir do hidrogênio passa a ser uma necessidade estratégica para garantir o atendimento às demandas energéticas dos próximos anos. 2,3 Células a combustível são dispositivos capazes de converter energia química em elétrica e térmica de forma direta, gerando corrente contínua por meio do suprimento de combustível e oxidante. 4 Dentre os diversos tipos de células a combustível existentes, as que usam uma membrana polimérica condutora de prótons (PEMFC) como eletrólito têm características que tornam seu uso viável tanto para geração estacionária de energia elétrica, quanto para aplicações portáteis e, até mesmo, automotivas (com uso de um motor elétrico). 2,4,5 Em um sistema de célula a combustível do tipo PEMFC, suprido com hidrogênio e oxigênio são conduzidas duas reações eletroquímicas parciais, em dois eletrodos separados por um eletrólito polimérico, formando água como produto da reação global e gerando energia elétrica e térmica com alta eficiência. As reações parciais e a reação global para hidrogênio e oxigênio são indicadas nas Equações 1, 2 e 3: 3,6 Ânodo: H 2 + 2 H 2 O à 2 H 3 O + + 2 e -(1)Reação global:Nessas reações o hidrogênio é oxidado no ânodo, os elétrons são conduzidos ao cátodo por um circuito externo, gerando corrente elétrica e os prótons são conduzidos ao cátodo através da membrana polimérica hidratada. 5,7,8 No cátodo ocorre a redução do oxidante na presença dos prótons e elétrons provenientes do ânodo, formando moléculas de água e fechando o circuito elétrico. 4,5,9 A estrutura onde as reações de uma PEMFC ocorrem é o conjunto eletrodo-membrana-eletrodo (MEA) -membrane electrode assembly. Esse conjunto é composto por uma membrana polimérica 5,7,8 faceada por dois eletrodos de difusão gas...

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Section: Introductionunclassified

Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC) por impressão a tela

Bonifácio¹,

Linardi²,

Cuenca³

2011

Quím. Nova

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“…Typically, the performance of a fuel cell improves at higher operation temperature due to lower activation loss. 17 However, the opposite behavior was found, as shown in Fig. 3b.…”

Section: Resultsmentioning

confidence: 79%

A Non-Flooding Hybrid Polymer Electrolyte Fuel Cell

Shen¹,

Prasad²,

Hertz³

2011

Electrochem. Solid-State Lett.

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Water management remains a major issue for polymer electrolyte-based fuel cells. This letter presents a novel hybrid polymer fuel cell that prevents flooding. A proton exchange membrane (PEM) and an anion exchange membrane (AEM) are placed on opposite sides of a porous, hydrophilic layer in which the product water is formed and then shunted to the exterior of the fuel cell. Maximum power output during these initial tests was 8 mW/cm 2 at 30 • C, somewhat less than comparable PEM and AEM fuel cells. Though the design is promising, potentiostatic tests at 70 • C indicate that maintaining hydration may be a concern. © 2011 The Electrochemical Society. [DOI: 10.1149/2.013111esl] All rights reserved.Manuscript submitted June 14, 2011; revised manuscript received July 26, 2011. Published September 23, 2011 Fuel cells based on proton exchange membranes (PEMs) are a promising electrochemical power source with high power density, low/zero emissions and quick start-up.1 Despite these advantages, commercialization has been impeded by several inherent limitations, including water management. In PEM-based fuel cells, water is produced at the cathode. Ideally, this product water together with a flowing, humidified reactant stream keeps the membrane correctly hydrated, yet prevents buildup of excess water.2 Unfortunately, this balance is difficult to achieve in practical devices, especially at low operating temperature or at high current discharge. 3,4 If the water removal rate falls behind the generation rate, liquid water can accumulate and block the pores in the electrode, preventing access for the reactants to the catalyst sites and significantly decreasing power output.5 Recently, researchers have started to examine fuel cells based on anion exchange membranes (AEMs), which feature significantly improved electrokinetics at the cathode.6-9 Water in these fuel cells is produced at the anode and thus flooding remains an issue, albeit now at the anode. 10A hybrid fuel cell was recently proposed byÜnlü et al.11-15 One of their designs used a Nafion R membrane with AEM ionomer as a thin layer on the cathode-facing surface and within the porous cathode structure.11, 12 At the PEM/AEM junction, protons from the PEM reacted with hydroxide ions from the AEM to form water.Ünlü et al. stated that the water could be used for membrane "self-hydration", and, as evidence, the performance of the hybrid fuel cell improved under lower relative humidity (RH) at 65• C. However, a rapid drop in performance at 40• C and 0% RH was observed.Ünlü et al. explained that this operating condition caused excessive "self-hydration" and flooding at the cathode. Hence, the problem of water flooding is not avoided in this hybrid fuel cell.Here we report a novel structure for a non-flooding hybrid polymer fuel cell, illustrated in Fig. 1. In this design, a PEM and an AEM are placed on the anode and cathode sides, respectively, of a thin, porous, hydrophilic membrane soaked with water. The hydrogen ions (H + ) conducted through the PEM and the hydroxide ions...

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“…38,39 In Figure 9, neutron radiographs at two different cell temperatures and RH ca (same current density) are shown. For a given condition (i.e.…”

Section: Resultsmentioning

confidence: 99%

Advanced Water Management in PEFCs: Diffusion Layers with Patterned Wettability

Forner‐Cuenca

Biesdorf

Manzi-Orezzoli

et al. 2016

J. Electrochem. Soc.

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Following our two previous publications on material synthesis and on ex situ characterization, we present an experimental in situ study to evaluate the effects of using gas diffusion layers with patterned wettability at the cathode side of polymer electrolyte fuel cells. The operando performance was assessed using traditional electrochemical diagnostics (such as polarization curves) combined with the pulsed gas analysis (PGA) method, which allows measuring the mass transport losses. Neutron radiography was performed simultaneously in order to image the water distribution during operation. Using this methodology, the effects of changing the pattern, including a microporous layer (MPL), and varying the operation conditions (temperature and relative humidity of the cathode gas) have been systematically evaluated. It has been confirmed that water redistributes according to the engineered pattern and that the power density is significantly increased thanks to reduced mass transport losses under various conditions. © The Author Several attempts have been reported in the literature to develop porous materials for fuel cells with optimized liquid/gas transport characteristic.1,2 The variation of microstructure 3,4 and the optimization of hydrophobic coatings and their content permitted significant improvements in performance, 5-9 while the inclusion of microporous layers led to the state-of-the-art materials that we know today. 10-17However, these materials do not have dedicated pathways for liquid and gas transport, but randomly distributed transport paths defined by the pore size and coating distributions.The perforation of GDLs in specific locations showed improved performances under certain operating conditions. 18,19 The local application of hydrophobic coatings was reported to improve oxygen diffusivity using an ex situ test rig combined with X-ray tomography. [20][21][22] An in situ study by the same research group demonstrated clear improvements when combining these hybrid GDLs with micro-grooved gas channels, but the isolated effect of hybrids GDLs did not lead to significant performance improvements. 23 Recently, we reported a method to produce GDLs with patterned wettability 24,25 based on radiation induced chemical grafting, and were the first to publish operando data with such patterned materials, showing a significant improvement when using them on the cathode of a PEFC. 25 Here, we present a comprehensive study on the impact of GDLs having patterned wettability on the water distribution and performance of the cell. The varied parameters include the dimensions of the pattern, the presence or absence of an MPL, and operating parameters such as humidity and temperature, respectively. This work currently rounds up a series of three papers including a detailed study on the material synthesis parameters (Part I) 26 and the analysis of the impact of various material parameters (substrate, coating load, grafting chemistry, pattern dimensions) on the water distribution in capillary injection experiments (Part II...

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A parametric study of PEM fuel cell performances

Cited by 570 publications

References 17 publications

Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC) por impressão a tela

Desenvolvimento de processo de produção de conjuntos eletrodo-membrana-eletrodo para células a combustível baseadas no uso de membrana polimérica condutora de prótons (PEMFC) por impressão a tela

A Non-Flooding Hybrid Polymer Electrolyte Fuel Cell

Advanced Water Management in PEFCs: Diffusion Layers with Patterned Wettability

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