Study On The Performance And Durability Influence Mechanism Of Electrospunp Pemfc Catalyst Layer

The electrospun fuel cell catalyst layer benefits from the fiber layer structure,has excellent power density and good durability,and has attracted extensive attention from the academic community.However,there are relatively few studies on the electro-spinnability of fuel cell slurry,and the mechanism by which fuel cell catalyst slurry components affect performance and durability is unclear.Therefore,this paper aims to start from the controllable preparation of electrospun fuel cell catalyst layers,study the influence of different ionomer contents and Pt loadings in the catalyst layer on the performance and durability of the catalyst layer,and reveal the corresponding effects in combination with characterization mechanism.First,study the electro-spinnability of the electrospun catalyst layer(CL),reveal the spinning behavior and fiber morphology changes.The results showed that with the increase of ionomer content,the reduction of particle size and the reduction of solid content,the frequency of blocking during electrospinning decreased significantly.Further explore the influence of different ambient temperature and humidity and applied voltage on the electrospinning behavior.In terms of the influence of temperature and humidity on the electrospinning behavior,the results show that as the temperature and humidity increase,the electrospinning behavior will experience normal spinning,semi-floating fibers,and standing fibers three stages;In terms of the influence of potential on spinning behavior,by fixing different negative voltages and changing positive voltages,the results show that as the potential increases,the electrospinning behavior will experience dripping,dripping with electrospinning,normal electrospinning and standing fiber four stages.Then,the performance of electrospun catalyst layer was compared with coated CL at low loading(0.1 mgPt/cm~2),and the results showed that the peak power density of electrospun CL was higher than coated CL 150%higher(0.62W/cm~2 for electrospun CL and 0.4 W/cm~2 for coated CL),showing better performance.Further research found that the electrospun CL had a higher electrochemically active surface area(ECSA)(57 m~2/gPt for electrospun CL and 40 m~2/gPt for coated CL)than the traditional coated CL.Under the same porosity,the electrospun CL has smaller mass transfer resistance(0.4 s/cm for electrospun CL and 0.6 s/cm for coated CL),and better mass activity(at a potential of 0.85 V,the CL is 0.106 A/mgPt for electrospun and 0.068 A/mgPt for coated CL).The effect of different I/C on the performance of electrospun CL was also investigated.The research results revealed that with the increase of I/C,the performance of the electrospun CL first increased and then decreased,with the best performance(0.62 W/cm~2)at I/C=0.6.Finally,the durability of the CL was studied through two typical working conditions of loading cycle and start-stop cycle.The results show that under the condition of low Pt loading(0.1 mgPt/cm~2),the electrospun and coated CLs have the same size Pt particle size after loading cycles.Under the condition of high Pt loading(0.3 mgPt/cm~2),the Pt particle size of the electrospun CL was smaller than coated CL after loading cycles.Under the loading cycle,the current density of electrospun CL at 0.6 V decreased by 20%,and the current density of coated CL decreased by 30%under the same conditions;The potential decays at 0.1 A/cm~2 were 20%and 32%,respectively.The results show that the durability of the electrospun CL is better than coated CL under loading cycle and start-stop cycle aging conditions.