Study On Improvement Of Preparation Technology Of Carbon Paper For Proton Exchange Membrane Fuel Cell

As the support of catalysts and the medium of electronic conduction,reactant gases distribution and water drainage,the carbon paper(CP)used as the gas diffusion layer(GDL)in Proton Exchange Membrane Fuel Cell(PEMFC)directly affects the performance of PEMFC.In this paper,the phenol resin which was used as impregnant in the process of CP preparation was modified to prepare CPs with better mechanical properties and physical performances.Firstly,the phenol resin was modified by PVB,which can not only improve the phase interface between matrix carbon and carbon fiber,but also make the matrix carbon form a good conductive network in CP.This paper mainly studied the effects of different PVB concentration on structure and performance of CP by means of double-impregnating method,meanwhile,the physical properties(intensity,porosity,gaspermeabilities,and electricalresistivities)and cells performance were also characterized.The results showed that with the increase of content of addition of PVB,the bending strength of CP increased from 36.75 MPa to 52.28 MPa;the electricalresistivity of CP decreased from12.63 m?·cm to 9.97 m?·cm;the porosity slightly increased,while the gaspermeability slightly decreased.In short,the CP modified with 0.06 g·ml-1 PVB exhibited the best comprehensive performances,the maximum out put power density was 76% higher than that of the original CP.Secondly,the above-mentioned modified CP(possessing the best comprehensive performances)was further modified by carbon black to improve its performance.Studies showed that carbon black enters into pores among the carbon fibers,which resulted in a good conductive network and meanwhile and changed the structure of matrix carbon.The structural as well as physicalproperties of CP modified by carbon black are also characterized,and the results showed that with the content of carbon black increasing,the thickness of the modified CP remains 0.170 mm;the strength,porosity,as well as gaspermeabilities decreased;and the electricalresistivities firstly increased from 10.58 m?·cm to 6.64 m?·cm,then decreased.Herein,the impacts of heat treatment temperature were also investi-gated to further improve the performances of CP.The improved strategy curves of carbonization were obtained by analysis of thermogravimetric analysis(TGA);and physical performances characterization exhibited that with heat treatment temperature increasing,the thickness,electrical resistivities,strength,porosity,and gaspermeabilities are all decreased.The researches on the influence of temperature on the thickness,electricalresistivities,strength,porosity,and gaspermeabilities of CP after different high-temperature processing,and can provide the reference datas on preparing CP with different properties.