1T‐WS2 Nanosheet‐Modified Biomass Carbon as Sulfur Host for High‐Performance Lithium–Sulfur Batteries

Abstract

The sluggish sulfur reaction kinetics and fast capacity attenuation still pose great challenges to lithium–sulfur (Li–S) batteries. Herein, tubular carbonl (HPOC) is obtained by carbonization of the cattail fiber. 1T‐WS2@HPOC is prepared by solvothermal method, and their sulfur composite, 1T‐WS2@HPOC/S and HPOC/S as sulfur host composite, is obtained by sulfur melting. The composite materials are characterized by scanning electron microscopy, X‐ray diffraction, thermogravimetry, X‐ray photoelectron spectroscopy, etc. Results show that 1T‐WS2 grows uniformly on the HPOC substrate and has abundant active sites, which can effectively improve the physicochemical adsorption capacity of S‐fixation (76 wt%) and polysulfide. Battery assembly and electrochemical performance tests are conducted for the HPOC/S and 1T‐WS2@HPOC/S composites. Results show that the initial discharge capacity of the 1T‐WS2@HPOC/S positive electrode is 1272 mAh g−1 at 0.1 C, higher than the HPOC/S positive electrode (1025 mAh g−1). 1T‐WS2@HPOC/S maintains a discharge capacity of 695 mAh g−1 after 500 cycles at 0.5 C, with a capacity decay rate of only 0.054% per cycle. With a discharge capacity of 504 mAh g−1 after 400 cycles at 1 C, the Coulomb efficiency is 98.9%. The 1T‐WS2@HPOC/S composites with unique structure and excellent electrochemical performance have broad application prospects in the field of Li–S batteries.