Simultaneous dual-defect engineering as a booster for polysulfide adsorption and conversion in Li-S battery

Abstract

Lithium-sulfur (Li-S) battery is considered as a burgeoning energy storage device owing to its high theoretical energy density. However, the shuttle effect and sluggish kinetics of sulfur species during conversion reactions lead to the challenges in attaining commercial application of high-performance Li-S battery. Herein, a double-defect engineering strategy is developed to endow CNT@Co3O4 with favorable effects on Li-S chemistry by introducing oxygen vacancies and phosphorus doped atoms (CNT@Co3O4-x-P). Experimental and theoretical investigations indicate that both enhanced adsorption and conversion of polysulfides can be realized on the surface of CNT@Co3O4-x-P. Taking advantage of the superb adsorption-conversion property of CNT@Co3O4-x-P, the cell achieves a specific capacity of 903 mAh/g with splendid cyclability at 2 C and a high areal capacity of 7.3 mAh cm−2 under the lean electrolyte (E/S = 6 μLE mg−1S) condition. This work offers a creative approach to implement high-performance Li-S batteries and promotes the application of Li-S batteries.