Effect of matrix content on the performance of carbon paper as an electrode for PEMFC

Abstract

Summary Porous conducting carbon fiber‐based composite paper is used as an electrode backing in the fuel cell assembly. It not only acts as a channel through which the reactant and product gases pass to and from the bipolar plate and the catalyst site but also helps in the flow of electrons. In order to perform its role efficiently, it should have sufficient strength, high electrical conductivity, and ideal porous structure. Carbon paper has been fabricated, which builds up the required composite properties. Studies have been conducted to optimize the fiber/matrix ratio in the carbon paper, while ensuring the perfect combination of porosity, mechanical strength, and electrical conductivity for an electrode in a proton electrolyte membrane fuel cells. Detail physico‐mechanical and electrochemical characterizations further ascertain that the fiber/matrix ratio plays an important role in tuning the composite properties. The polarization curve of the unit proton exchange membrane (PEM) fuel cell (with an effective electrode area 4 cm2) shows a peak power density of 916 mW/cm2 for the sample with fiber/matrix ratio of 65:35, which is almost the same as the commercially available sigracet gas diffusion layer (SGL) carbon paper tested under similar conditions. Further, proportionally enlarging the electrode area to 100 cm2 shows that the carbon paper not only shows almost repeatable results in a given set up but also scales up.

Configuring the Porosity and Microstructure of Carbon Paper Electrode Using Pore Formers and Its Influence on the Performance of PEMFC

“…Preparation and Processing of Carbon Paper. Carbon paper has been prepared by the process of papermaking, 43 followed by composite formation. 33,47 Macroporous preforms were made from carbon fibers in the form of a nonwoven mat structure, as mentioned previously.…”

“…33,43 These preforms were impregnated with the solution of calculated amounts of phenolic resin and HMTA in acetone. 43 Additionally, pore formers (20% by weight of phenolic resin) were added into the above-mentioned solution and mixed homogeneously with the resin using ultrasonication. The preforms were impregnated with the solution using the hand lay-up process, whereby the latter was poured and spread over the preform and distributed evenly over the entire region using a glass rod.…”

Effect of composition and structure of gas diffusion layer and microporous layer on the through‐plane gas permeability of PEFC porous media

“…The main functions of the GDM are to distribute the reactant gases uniformly and efficiently to the CL, improve the electrical contact with the CL, allow the flow of electrons and heat, and facilitate the removal of excess liquid water away from the electrodes to the flow channels. 1,6,12 GDM fabrication typically describes the altering of the GDL substrate by the addition of a hydrophobic material such as PTFE or the addition of a thin layer referred to as an MPL, which consists of carbon powder and a binding/hydrophobic agent such as PTFE followed by a heat treatment step. The physical properties of this thin layer are determined from the type, loading and particle size of the carbon powder used in conjunction with the type of hydrophobic agent, such that the former controls the surface morphology and the latter the pore properties.…”

“…The GDM typically consists of a gas diffusion layer (GDL) attached to a microporous layer (MPL) with the GDL situated nearer to the flow‐field plate (FFP) and the MPL adjacent to the catalyst layer (CL). The main functions of the GDM are to distribute the reactant gases uniformly and efficiently to the CL, improve the electrical contact with the CL, allow the flow of electrons and heat, and facilitate the removal of excess liquid water away from the electrodes to the flow channels 1,6,12 …”

Boron‐Catalytic Graphitization Boosting the Production of High‐Performance Carbon Paper at a Moderate Temperature

“…[4] The pyrolytic carbon matrix derived from resin is nongraphitizable. Thus the graphitization at a high temperature (>2000 C) is applied as an important measure to improve the electrical conductivity and chemical resistance of the CPs, [5][6][7][8][9][10] but counting for high energy consumption. Some other strategies are used to improve the electrical conductivity of nongraphitizable matrices, such as adding carbonaceous additives including carbon black, Ketjenblack, natural graphite, expanded graphite, and graphene oxide, into impregnating resin.…”