In-situ conversion method for Co9S8 embedded in N-doped carbon derived from resin waste induced ultra-stable Li-S batteries

Abstract

The effective suppression of the shuttle effect in lithium-sulfur batteries require the development of efficient electrocatalysts. Transition metal sulfides show great potential as S cathode electrocatalysts. However, the conventional secondary sulfidation or heat-treatment process used in their synthesis limits their catalytic performance. In this study, we propose an efficient and scalable “exchange-constriction-in-situ conversion” strategy to prepare Co9S8@NC electrocatalysts using CoSO4 and waste resins as sources. No additional sulfur source is required in this process. The resulting Co9S8@NC catalyst demonstrates outstanding long-cycle performance, with a slight decay of only 0.028 % per cycle after 500 cycles at a current density of 2 C. Moreover, it exhibits excellent electrochemical performance even at high surface loading and low electrolyte dosage (E/S). The combination of theoretical calculations and electrochemical analyses demonstrates that Co9S8 possesses strong adsorption, superior catalytic capacity and lower energy barrier of decomposition towards lithium polysulfide, consequently leads to an enhancement in reaction kinetics. This study presents a novel approach for synthesizing high-performance sulfide electrocatalysts.