Li–S battery cathode anchoring polysulfides by interaction between redox-active imide and carbon nanotube

Abstract

Providing high energy density and theoretical capacity, lithium-sulfur (Li–S) battery technologies emerged as a suitable alternative to the existing lithium-ion batteries (LIBs) at low cost. However, insulating nature of sulfur, dissolution of polysulfides into the aprotic electrolyte solvent as well as volume changes upon cycling cause rapid capacity decay. One of the effective strategies is the usage of redox active functional organic materials to trap polysulfides or utilization of conductive carbon materials to overcome lower electronic conductivity of the sulfur active material. In this work, N–N′-diphenyl-1,4,5,8-naphtalene-tetra-carboxylic-diimide (DP-NTCDI) is efficiently synthesized and mixed with single-walled carbon nanotube (SWCNT) to both serve as polysulfide adsorbent and conductive agent role. After the detailed structural characterization, density functional theory (DFT) analysis as well as adsorption tests, the electrochemical performances of the Li–S cell performances are evaluated in which the discharge value over 330 mAh/g at C/5 after 150 cycle is achieved with 85 wt% sulfur containing electrode.