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Structure,property,and Performance of Catalyst Layers in Proton Exchange Membrane Fuel Cells

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Electrochemical Energy Reviews 2023年第1期6卷 403-463页

作者： Jian Zhao Huiyuan Liu Xianguo Li Department of Mechanical and Mechatronics Engineering University of Waterloo200 University Avenue WestWaterlooON N2L 3G1Canada

Catalyst layer(CL)is the core component of proton exchange membrane(PEM)fuel cells,which determines the performance,durability,and cost.However,difficulties remain for a thorough understanding of the CLs’inhomogeneous structure,and its impact on the physicochemical and electrochemical properties,operating performance,and durability.The inhomogeneous structure of the CLs is formed during the manufacturing process,which is sensitive to the associated materials,composi-tion,fabrication methods,procedures,and conditions.The state-of-the-art visualization and characterization techniques are crucial to examine the CL structure.The structure-dependent physicochemical and electrochemical properties are then thoroughly scrutinized in terms of fundamental concepts,theories,and recent progress in advanced experimental techniques.The relation between the CL structure and the associated effective properties is also examined based on experimental and theoretical findings.Recent studies indicated that the CL inhomogeneous structure also strongly affects the performance and degradation of the whole fuel cell,and thus,the interconnection between the fuel cell performance,failure modes,and CL structure is comprehensively reviewed.An analytical model is established to understand the effect of the CL structure on the effective properties,performance,and durability of the PEM fuel cells.Finally,the challenges and prospects of the CL structure-associated studies are highlighted for the development of high-performing PEM fuel cells.

关键词： PEM fuel cell Catalyst layer Microstructure effective property Performance Durability

EXTENSION OF COMBINED SELF-CONSISTENT AND MORI-TANAKA APPROACH TO EVALUATION OF ELASTOPLASTIC property OF PARTICULATE COMPOSITES

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Acta Mechanica Solida Sinica 2013年第1期26卷 71-82页

作者： Xianghe Peng Ning Hu Xuesong Long Hengwei Zheng Department of Engineering Mechanics Chongqing University State Key Laboratory of Coal Mine Disaster Dynamics and Control Chongqing University Department of Mechanical Engineering Chiba University

The combined self-consistent and Mori-Tanaka approach proposed for the evaluation of the effective elastic property of particulate composites is extended to evMuate the effective elastoplastic property of particulate composites. Suppose there are sufficient identical particle inclusions with total volume fraction c in a representative volume element （RVE） of a particulate composite, these inclusions are separated into two groups, with volume fractions （1 -A-1）c and c/A over the RVE, respectively. We assume that the first group of inclusions has already been embedded in the original matrix to form a fictitious matrix, and the RVE of the composite consists of the fictitious matrix and the second group of particle inclusions. The property of the fictitious matrix is determined by the conventional self-consistent scheme, while the effective elastoplastic property of the composite is determined by the conventional Mori-Tanaka scheme. Analysis shows that, the conventional Mori-Tanaka scheme and self-consistent scheme can be obtained as the two limit cases of the extended approach as A = 1 and A = c~, respectively. The constitutive behavior of the inclusions in either Group I or Group II is identical, indicating the consistency in the description of the constitutive behavior in the two steps. ~klrthermore, the effective elastoplastic behavior of some typical particulate composites is analyzed, and the satisfactory agreement between the computational and experimental results demonstrates the validity of the extended approach. The introduced A can serve reasonably as a parameter, which is related to the actual property of composites and can be identified by experiments, for a more accurate evaluation of the effective elastoplastic property of particulate composites.

关键词： particulate composite elastoplasticity effective property combined self-consistent and Mori-Tanaka approach

Influences of interphase on dynamic effective properties of composites reinforced by dispersed spherical particles

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Journal of University of Science and Technology Beijing 2006年第3期13卷 256-262页

作者： Peijun Wei Lili Gu Applied Sciences School University of Sciences and Technology Beijing Beijing 100083 China Tangshan Iron ＆ Steel Group Co. Ltd Tangshan 063016 China

The influences of interphase on dynamic effective properties of composites reinforced by randomly dispersed spherical particles were studied. A thin homogeneous elastic interphase with different shear and bulk moduli, located between the reinforced particle and the host matrix, was introduced to model the interfacial bonding state. The effects of such an interphase on the coherent plane waves were studied numerically. Numerical simulations were carried out for SiC-Al composites with four typical cases of interphase. It was found that the property of interphase has significant influences on the effective propagation constants of coherent waves and the dynamic effective elastic moduli of the composites. The influences on the coherent longitudinal wave and the coherent shear waves were different and dependent upon the frequency range. Moreover, several imperfect interface models, i.e., the spring model, mass model, and spring-mass model, were studied numerically and compared with the interphase model, It was found that the spring model is a more suitable model than the mass model for the light and weak interphase whereas the mass model is a more suitable model than the spring model for the heavy and strong interphase.

关键词： composites effective property coherent wave interface model interphase multiple scattering

APPLICATION OF A NEW FAST MULTIPOLE BEM FOR SIMULATION OF 2D ELASTIC SOLID WITH LARGE NUMBER OF INCLUSIONS

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Acta Mechanica Sinica 2004年第6期20卷 613-622页

作者：王海涛姚振汉 Department of Engineering Mechanics Tsinghua UniversityBeijing 100084China

A fast multipole method(FMM)is applied for BEM to reduce both the operation and memory requirement in dealing with very large scale problems.In this paper,a new version of fast multipole BEM for 2D elastostatics is presented and used for simulation of 2D elastic solid with a large number of randomly distributed inclusions combined with a similar subregion approach.Generalized minimum residual method(GMRES)is used as an iterative solver to solve the equation system formed by BEM iteratively.The numerical results show that the scheme presented is applicable to certain large scale problems.

关键词： boundary element fast multipole 2D elastic solid with inclusions GMRES effective property

RANDOM MICROSTRUCTURE FINITE ELEMENT METHOD FOR effective NONLINEAR PROPERTIES OF COMPOSITE MATERIALS

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Journal of Wuhan University of Technology(Materials Science) 2000年第2期15卷 1-6页

作者：瞿鹏程 Wuhan University of Technology China State Key Lab. Mat. Synthesis Proc. Wuhan University of Technology Wuhan 430070 China

Some theoretical methods have been reported to deal with nonlinear problems of composite materials but the accuracy is not so good. In the meantime, a lot of linear problems are difficult to be managed by the theoretical methods. The present study aims to use the developed method, the random microstructure finite element method, to deal with these nonlinear problems. In this paper, the random microstructure finite element method is used to deal with all three kinds of nonlinear property problems of composite materials. The analyzed results suggest the influences of the nonlinear phenomena on the effective properties of composite materials are significant and the random microstructure finite element method is an effective tool to investigate the nonlinear problems.

关键词： random microstructure finite element method effective property composite materials nonlinear property problems

RANDOM MICROSTRUCTURE FINITE ELEMENT METHOD AND ITS VERIFICATION FOR effective PROPERTIES OF COMPOSITE MATERIALS

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Journal of Wuhan University of Technology(Materials Science) 2000年第1期15卷 6-12页

作者：翟鹏程 Wuhan University of Technology China State Key Lab. Mat. Synthesis Proc. Wuhan University of Technology Wuhan 430070 China

The present study aims at developing a new method-RandomMicrostructure Finite Element Method (RMFEM) for the effectiveproperties of com- Posite materials. In this method, a randommicrostructure Model is used to simulate the microstructure of thereal composite materials. The physical fields in such a randomMicrosturucture model under specified boundary and initial Conditionsare analyzed by finite element method.

关键词： random microstructure finite elment method effective property compositematerials