摘要
The conversion of agricultural residual biomass into biochar as a sulfur host material for Li-S batteries is a promising approach to alleviate the greenhouse effect and realize waste resource reutilization.However,the large-scale application of pristine biochar is hindered by its low electrical conductivity and limited electrocatalytic sites.This paper addressed these challenges via the construction of Fe-N co-doped biochar(Fe-NOPC)through the copyrolysis of sesame seeds shell and ferric sodium ethylenediaminetetraacetic acid(NaFeEDTA).During the synthesis process,NaFeEDTA was used as an extra carbon resource to regulate the chemical environment of N doping,which resulted in the production of high contents of graphitic,pyridinic,and pyrrolic N and Fe-Nx bonds.When the resulting Fe-NOPC was used as a sulfur host,the pyridinic and pyrrolic N would adjust the surface electron structure of biochar to accelerate the electron/ion transport,and the electropositive graphitic N could be combined with sulfur-related species via electrostatic attraction.Fe-Nx could also promote the redox reaction of lithium polysulfides due to the strong Li-N and S-Fe bonds.Benefiting from these advantages,the resultant Fe-NOPC/S cathode with a sulfur loading of 3.8 mg·cm^(-2)delivered an areal capacity of 4.45 mAh·cm^(-2)at 0.1C and retained a capacity of 3.45 mAh·cm^(-2)at 1C.Thus,this cathode material holds enormous potential for achieving energy-dense Li-S batteries.
基金
supported by the National Natural Science Foundation of China(No.21808053)
the Postgraduate Scientific Research Innovation Project of Hunan Province,China(No.CX20210659)。
