Interface engineering of heterostructural quantum dots towards high-rate and long-life lithium-sulfur full batteries

Abstract

Despite being as next-generation energy storage systems with ultra-high theoretical energy density of 2600 Wh kg⁻¹, lithium-sulfur (Li-S) batteries face serious hurdles due to the sluggish redox kinetics in S cathodes and uncontrollable growth of dendrites in Li anodes. To simultaneously address such issues, herein, we present an interface engineering strategy to develop a dual-functional host for S cathode and Li anode, which is constructed by heterostructural WC-WN_0.67 quantum dots homogeneously embedded in N-doped graphene nanosheets (WC-WN_0.67@NG). As a result, the Li-S full batteries deliver a high reversible capacity of 704 mA h g⁻¹ even at a high rate of 4 C, and demonstrate a long-term cycling stability even at 2 C with a low degradation rate of 0.027 % over 1200 cycles. This work paves the way to facilitate the practical applications of Li-S batteries through interface engineering of dual-functional heterostructural quantum-dot host.