Atomic Layer Deposition of Single Atomic Cobalt as a Catalytic Interlayer for Lithium-Sulfur Batteries

Lithium-sulfur (Li-S) batteries have been considered as one of the most promising next-generation rechargeable battery technologies owing to the high theoretical energy density and the low cost of sulfur resources. However, the practical implementation of Li-S batteries is largely impeded by the sluggish conversion kinetics and the "shuttling effect" of soluble polysulfides intermediates bearing a long short cycling life and an inferior rate performance. Herein, single atomic cobalt-decorated free-standing CNT (CNT@SACo) films are prepared by the atomic layer deposition method and used as the multifunctional interlayer for high-performance Li-S batteries. Experimental results and theoretical calculations indicate that the CNT@SACo interlayer demonstrates catalytic activity to improve the electrochemical conversion kinetics of polysulfide and strengthen the affinity of cathode toward polysulfide. Consequently, the Li-S batteries with a CNT@SACo interlayer demonstrate a high capacity of 880 mAh g(-1) at a current density of 1C with a low capacity decay rate of 0.064% per cycle over 500 cycles. Even at a high current density of 2C, the battery still exhibits a high capacity of 641 mAh g(-1). Our work demonstrates a feasible and practical design approach for endowing nanomaterials with targeted functions for high-performance lithium batteries.