Preparation Of Co-N_x-based Polymer,Porous Carbon And Its Application In Energy Storage

The oxygen reduction reaction(ORR)kinetics of the zinc-air battery is slow,and the atomic-level dispersion of Co-Nx has been proven to efficiently catalyze the oxygen reduction reaction.However,it is difficult to obtain a stable Co-Nx-based material structure after high temperature pyrolysis,we can’t get Co-Nx active center.In this thesis,by constructing a polymer rich in Co-Nx active structure on the surface of carbon nanotubes,the relationship between the structure,composition,surface and interface properties of the composite material and the catalytic oxygen reduction reaction performance was systematically studied.Activated carbon materials used in supercapacitors are expensive and low in capacitance.The preparation of cheap,high-capacity carbon materials is an important way to improve the performance of supercapacitors and reduce costs.This paper selects cheap industrial coal needle coke as the raw material,uses the activator(KOH)to activate,obtains the carbon material with the porous structure,and studies the capacitance performance of the material.The main research results are as follows:1)Construct and synthesize polymers with Co-Nx structure,and study the effects of different ratios of carbon nanotubes,metals and ligands on the oxygen reduction catalytic activity of the materials.The results show that the molar ratio of metallic cobalt to ligand(1,2,4,5-tetraaminobenzene)is 2:1,and when the doping amount of carbon nanotubes is 30%(80 mg),the obtained material(CN4-2Co@80CNTs)show a good Performance at oxygen reduction catalysis,and the half-wave potential is 0.83 V.Under the same conditions,the measured oxygen reduction half-wave potential of a commercial 20%Pt/C catalyst is 0.91 V vs RHE.The material CN42Co@80CNTs is applied to zinc-air battery,the maximum power density is 94.5 mW/cm2(corresponding to the current density of 145.2 mA/cm2),when the current density is 10 mA·cm-2,it can be continuously and stably discharged for 19 h.2)The precursor obtained from the pre-coking treatment of coal needle coke is used as the raw material,and KOH is selected as the activator.The effect of the mass ratio between the precursor and KOH and the activation temperature on the structure and electrochemical performance of the synthesized porous carbon material is studied.The experimental results show that when the mass ratio of Precursor and KOH is 1:3,the synthesized porous carbon material(coal-3KOH-750)has a relatively high BET area of 1633 m2/g,and when the current density is 0.2 A/g,The capacitance is 237 F/g,which is about twice that of traditional commercial activated carbon.The current density is 0.5 A/g,after 3000 cycles of constant current charging and discharging,the capacitance performance is maintained at about 92%,which has high stability.