Preparation Of Biochar Material Modified Separator And Its Application In Lithium-sulfur Battery

In the context of the national "double carbon" goal,energy conservation,emission reduction and energy transformation are the basic path to achieve the "double carbon" goal on schedule.Energy conservation,emission reduction and energy transformation are inseparable from technical support,in which new energy technology is the key link.Lithium sulfur battery not only has high capacity and energy density,but also has low cost and no pollution to the environment.Therefore,it has great development and application prospects in new energy technology.However,the short cycle life,serious capacity attenuation and low coulomb efficiency of lithium sulfur battery hinder its application.These are related to the "shuttle effect" caused by sulfur intermediates in the process of charge and discharge,which hinders the cycle performance of the battery.Therefore,in order to obtain high-performance lithium sulfur batteries,materials with special structure and properties must be prepared to inhibit the diffusion of polysulfides in order to deal with the shuttle effect caused by intermediates in lithium sulfur batteries.To use nano-materials as the conductive framework of high-performance sulfur cathode materials is the main method,so as to minimize the loss of soluble polysulfide intermediates in the cycle process and achieve the purpose of high capacity and long cycle life.However,these methods usually involve complex synthesis processes,which hinder the practical application of lithium sulfur batteries.Recently,high-performance biomass carbon as battery separator has attracted much attention,because biomass carbon has strong adsorption performance,which can effectively hinder the shuttle effect caused by polysulfide intermediates,promote the chemical conversion of lithium polysulfide and improve the electrochemical performance of battery.Moreover,biomass carbon has attracted great attention because of its wide source and low price.In this paper,manganese doped biomass carbon separator was prepared from agricultural waste straw after a series of treatment.In addition,the biomass carbon load separator has good performance in the reaction of lithium sulfur battery under long-time cycle and high load system.More importantly,when sulfur load is 6 mg,the thickness of lithium foil is 50 μ m and the severe condition of E / S is 5,the modified sample still has higher capacity and retention.Through a series of analysis experiments,the mechanism of improving electrochemical performance of biomass carbon separator was systematically studied.This work provides more useful exploration for the application of biomass carbon and the commercial application of Lithium-sulfur battery.