REVIEW ON MOLYBDENUM-BASED CATALYSTS AND THEIR CATALYTIC MECHANISM FOR LITHIUM-SULFUR BATTERIES

Abstract

Lithium-sulfur (Li-S) batteries are treated as a promising candidate for the next generation energy storage systems due to their high theoretical specific energy of 2500 Wh kg−1. However, the slow solid-liquid-solid reaction kinetics of sulfur cathodes and the shuttle effect of lithium polysulfides (LiPSs) intermediates during cycling hinder their further application. Introducing suitable catalytic materials into the sulfur cathode can facilitate the kinetics of Li2S4reduction and Li2S oxidation, thereby enhancing the electrochemical reaction kinetics and improving the energy storage performance of Li-S batteries. However, the structure-activity relationship between the electronic structure of catalysts, the reduction of Li2S4and the oxidation of Li2S remains unclear. Molybdenum (Mo) based metal compounds, with their high conductivity and catalytic activity, have been widely used in Li-S batteries. Mo can form different crystal phases, compositions, and electronic structures of Mo-based metal compounds with elements such as C, N, O, and P, making the Mo-based compounds a good research platform for studying the structure-activity relationship between electronic structure and the performance of catalytic materials. Herein, we review the recent advances of cathodic modification strategy for Li-S batteries. Moreover, the catalytic performance of Mo-based catalysts and their electronic structure regulation, and catalytic mechanism revealing are also discussed.