Preparation of three-dimensionally interconnected sulfur-deficient MoS2/nitrogen-doped carbon composite via salt template method for separator modification in lithium–Sulfur batteries

Abstract

Separator modification is a promising strategy with regard to lithium–sulfur batteries for trapping polysulfides and suppressing the involved shuttle effect. Herein, a sulfur-deficient molybdenum disulfide/nitrogen-doped carbon composite with an open and interconnected structure (IMoS2-x) was synthesized through facile salt template method using recrystallized salt powder. Unlike the two-dimensional sheet structure obtained through conventional salt template method, an effective three-dimensional IMoS2-x composite design can be achieved using small salt powder as a template. The prepared IMoS2-x-coated polypropylene separator (referred to as IMoS2-x/PP) exhibited remarkable electrochemical performances such as high initial discharge capacity of 1405.1 mAh/g and rate capability of 754.16 mAh/g at 0.1 and 3C, respectively. Furthermore, IMoS2-x/PP exhibited robust cycling performance of 911.18 mAh/g after 80 cycles at 0.2C under high sulfur loading and lean electrolyte conditions, with the electrolyte-to-sulfur ratio (E/S ratio) of 7.5 μL mg−1.