Study On Preparation And Electrochemical Performance Of Carbon Materials Derived From Peanut Shell

In the modern era with the rapid development of economic globalization and the increasingly updated innovative high-tech products,the consumption of fossil energy has gradually increased,which has led to the increasing problem of environmental pollution.Based on these problems,the creation and development of new types of green renewable energy and efficient energy conversion and storage equipment has become an indispensable task.Among them,supercapacitors have received extensive attention because of their fast charge-discharge and energy storage characteristics.However,the key to the performance of supercapacitors lies in the choice of electrode materials.Usually the electrode materials we use are activated carbon,graphene,carbon nanofibers,etc.,but the process of preparing activated carbon from these materials is not only dangerous,but also expensive.Therefore,research on green,environmentally friendly,cheap and easy-to-obtain biomass carbon materials has attracted the attention of researchers.On this basis,the biomass-derived carbon material we used not only has a simple preparation process,but also has strong plastic properties.The structure was characterized by SEM,XRD,BET,XPS and other means,and its electrochemical performance was studied.The results are as follows:（1）Using peanut shells,which are abundant and low-priced wastes,as carbon precursors,and urea and thiourea as N sources and N and S sources,respectively,N-doped carbon materials（NAC）and N,S CO-Doped carbon material（NSAC）.The experimental results show that when the mass ratio of urea and thiourea to activated carbon is 2:1,the best conditions are when the carbonization temperature is 900 ⁰C.The prepared NAC and NSAC are used as electrode materials,and 6 M KOH is used as the electrode material.Electrolyte,passed the electrochemical performance test:at a current density of 0.2 A g^-1,the mass specific capacitances were tested to be 80.80 F g^-1 and 90.36 F g^-1 respectively;after 2000 cycles measured by experiments(The current density is 10 m A g^-1),and its capacitance still reaches97.82%of the initial capacitance,showing excellent cycle stability.Because the prepared NSAC has good plasticity,we press it into a miniature 3D interdigital shape with PVA/H₂SO₄as the electrolyte,and the prepared symmetrical supercapacitor has a surface capacitance of715.73 m F cm^-2.(The surface capacitance of general carbon materials is 200 m F cm^-2).This work not only enhances the surface capacitance of the miniature supercapacitor,but also improves its practical applicability because of its better plasticity.（2）Asymmetric supercapacitors are characterized by high energy density due to their high voltage window.Therefore,we use zinc as the anode,NSAC as the cathode,and zinc trifluoromethanesulfonate as the electrolyte.The voltage window of the zinc ion hybrid supercapacitor prepared reaches 1.75 V（the voltage window of the symmetrical supercapacitor made of general carbon materials is 0.8V）.It has greatly improved its energy density,and the surface capacitance has reached 663.89 m F cm^-2.It has the feasibility of commercialization.