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.