Promoting sulfur redox reactions by CuBr quantum dot-based electrocatalyst for lean-electrolyte lithium-sulfur batteries

Abstract

The construction of robust electrodes with promoted kinetics of sulfur redox reactions and enduring redox chemistry is crucial for developing advanced Li-S batteries. Herein, a hybrid sulfur cathode based on CuBr quantum dots (QDs)-interspersed reduced graphene oxide (rGO) is first developed for energy-dense Li-S batteries. With the combination of theoretical calculations and experimental results, it is certified that the CuBr QDs anchored on the rGO surface could efficiently improve the chemical adsorption and transformation of sulfur-related species, which significantly facilitates desired redox reaction, thus resulting in a durable and fast long-term cycling performance. Under practically-relevant conditions, the assembled pouch cell could deliver a high initial gravimetric energy density of 375 Wh kg−1 with decent durability, showing great application prospects in lean-electrolyte Li-S batteries.