Development And Performance Research Of Proton Membrane Fuel Cell/supercapacitor For Energy Conversion And Storage

The ever-increasing fossil energy crisis and environmental crisis have urged people to vigorously develop and utilize new energy,and the new energy automobile industry has ushered in opportunities and challenges.At present,lithium-ion battery vehicles occupy a dominant position in the market,but they have the problem of long charging time.Fuel cell vehicles can be refueled in minutes,but they are expensive,so it is meaningful to develop low-cost fuel cell proton exchange membranes.In addition,when the fuel cell is used as a single power source,there are problems such as soft output characteristics and waste of braking energy,and supercapacitors with fast charge-discharge and high specific capacitance characteristics are suitable for compensating for the high power output of fuel cells and recovering the energy of the braking process.In order to improve the performance of supercapacitors,it is meaningful to develop high-performance electrode materials.In response to the above problems,this paper has developed low-cost proton exchange membranes and high-performance biomass electrode materials in a fuel cell/supercapacitor hybrid power system.The main work is as follows:（1）In this paper,inexpensive PTFE is used as the substrate,and the surface of the hydrophobic PTFE material is designed,and a small amount of Nafion and PTFE are used to compound the low-cost proton membrane.The hydrophobic PTFE surface is first modified with acrylic acid to make the water contact angle reduced from 150°to 55.6°,sprays hydrophilic Nafion to complete the preparation of low-cost PTFE/PAA/Nafion composite proton exchange membranes（saving 60%of Nafion dosage）.The mechanical strength and dimensional stability of the composite membrane（breaking strength of 25.2 MPa,swelling rate of 11.9%at 80°C）are better than those of Nafion117 membrane.The composite membrane has high proton conductivity(131.9 m S cm^-1 at 80°C),which is close to Nafion117 membrane,and the maximum power density can reach 404.2 m W cm^-2,which proves that the PTFE/PAA/Nafion composite membrane can be used as a proton exchange membrane.（2）Biomass carbon,which has a wide range of sources and is cheap,is suitable for the development of electrode materials.In this paper,we select the biomass-eggplant with its own porous structure as the raw material,and prepare the EHPC electrode material through freeze-drying-pre-carbonization-activation-activation-high-temperature carbonization.EHPC-1000has a large amount of ordered graphitized carbon（I_G/I_D=1.14）,high porosity(1.264 m³ g^-1),high specific surface area(1947.37 m² g^-1),and exhibits high electrical conductivity(6.98 S cm^-1),good rate performance,excellent specific capacitance(469 F g^-1 at 1 A g^-1)and good capacitance retention(81%at 50 A g^-1),etc.The electrochemical performance shows that EHPC-1000 has the potential for commercial application in supercapacitor electrode materials.