Preparation And Properties Of N,s-codoped Carbon-based Air Electrode For Zinc Air Flow Battery

The development of wind energy and solar energy renewable energy power has become an inevitable choice for the sustainable development of human society.However,renewable energy power has discontinuous and unstable characteristics and needs to be equipped with energy storage technology.Zinc air flow battery has the advantages of high energy density,long life and low cost,and become one of the preferred technologies for large-scale energy storage.However,due to the slow kinetics of the oxygen reduction and oxygen evolution of the anode electrode,the polarization of the battery has increased,and the low efficiency limits its development.There is an urgent need to develop non-metallic dual-function air electrodes to establish the performance-structure relationship of non-metal based air electrodes.The research contents of this thesis are as follows:1.Developed a three-dimensional conductive matrix in-situ growth catalytic component to construct an integrated air electrode.Growth of 2-amino-5-mercapto-1,3,4-thiadiazole(PAMT)on the surface of three-dimensional carbon fiber paper by electropolymerization after high temperature cracking,carbon fiber paper wrapped with nitrogen-sulfur co-doped carbon(NSC)is obtained.The effects of calcination temperature and PAMT electropolymerization on the structure and composition of air electrode were researched.The calcination temperature in the range of 800-1000? mainly affects the pore structure of the air electrode,and the carbonization is not sufficient when the temperature is low(800?).The pore structure collapses at a high temperature(1000?).The air electrode obtained at 900? has the highest specific surface area(360 m2 g-1)and pore volume(0.29 cm3 g-1);increasing the amount of PAMT polymerization can increase the nitrogen and sulfur content in the air electrode,but the PAMT content is excessively high(125 circles),the defect content is reduced.2.The relationship between the structure and performance of air electrode was researched by the combination of electrochemical test and spectroscopy.The research shows that NSC film provides abundant active sites,and heteroatom doping and defects can produce catalytic activity center,graphite N and pyridine N are favorable for oxygen reduction reaction,graphite N is favorable for oxygen evolution reaction;conductive CFP of 3D macro network provides convenient channel for electron and mass transfer;due to the synergistic effect between NSC and CFP CFP@NSC-900 exhibits superior ORR(E1/2,0.804 V,half-wave potential comparable to commercial Pt/C)and high catalysis of OER(E10,1.715 V,lower potential than commercial IrO2)activity and stability.3.CFP@NSC-900 exhibits a lower charging voltage and a higher discharge voltage in a zinc air flow battery than an electrode coated with Pt/C and IrO2 on a CFP.With excellent cycle stability,performance is not attenuated in 3400 minutes,and voltage efficiency is 58%,better than 53%of Pt/C+IrO2.