Preparation And Properties Of Nitrogen Sulfur Co-doped Hierarchically Material For Zinc Air Battery

Zinc air battery has low cost,high safety and high energy density,which has a broad application market in the field of dynamical system and energy storage.However,the kinetics of cathodic oxygen reduction reaction is slow and lacks efficient and inexpensive catalytic materials.This paper focuses on the preparation and performance of low-cost,high-performance metal-free oxygen reduction catalysts,and carries out the following research contents:First,A new method for preparing nitrogen and sulfur co-doped hierarchically porous carbon materials from rigid template was developed.The nitrogen-sulfur-rich covalent organic polymer(N-S-COP)is used as a self-template and carbonized to obtain nitrogen and sulfur co-doped hierarchically porous carbon(HPNSC).Scanning electron microscopy,nitrogen absorption-desorption and electrochemical test results show that HPNSC not only retains the macro structure of N-S-COP,but also has a richer microscopic pore structure,BET specific surface area is up to 1261 m2 g-1,the half-wave potential of oxygen reduction is 20 mV higher than the commercial Pt/C catalyst.Second,Explore the structure-activity relationship between catalytic properties and pore structure.By changing the carbonization temperature,controlling the pore structure and elemental composition of the catalyst,the relationship between the pore structure of the catalyst and the electrochemical active area and mass catalytic activity was preliminary studied.The results show that the electrochemical specific surface area is mainly composed of mesopores and macropores,and the contribution of micropores is small.The electrochemical specific surface area of HPNSC is as high as 429 m2 g-1;Only heteroatoms doped in the electrochemically active area can create an effective active site and thus catalyze the oxygen reduction reaction;metal-free oxygen reduction catalyst with the highest mass activity is created,up to 126.7 mA mg-1@0.8 V,which is seven times that of commercial Pt/C.Third,The peak power density of primary zinc air battery with HPNSC as cathode catalyst is as high as 144 mW cm-2,which is much higher than commercial Pt/C(110 mW cm-2),and the energy density is as high as 1007 W h kgZn-1,higher than other metal-free based zinc air batteries.