Core-Shell CuS@MoS2 Cathodes for High-Performance Hybrid Mg-Li Ion Batteries

Abstract

With high theoretical specific capacity and favorable electrochemical properties, CuS is considered to be the ideal cathode material for hybrid Mg-Li ion batteries. However, the traditional CuS cathodes exhibit inferior rate performance and poor cycle stability, which limits the development and application of CuS. In this work, CuS@MoS2 with core–shell structure was prepared by two-step hydrothermal synthesis. When utilized for hybrid Mg-Li batteries, CuS@MoS2 displayes high special capacity and stable cycling performance. At current density of 50, 100 and 300 mAg−1, the first discharge capacity is 337.40, 276.28 and 254.58 mAhg−1 which are all higher than those of single CuS and MoS2. More importantly, the discharge capacity of core–shell CuS@MoS2 can remain 104.70 mAhg−1 at 100 mAg−1 after 50 cycles. These performance improvements are contributed to rich reaction sites and high conductivity of mixed metal sulfides. Furthermore, core–shell structure could relieve the volumetric change and remain structure stability for active materials. In conclusion, core–shell CuS@MoS2 could offer a new strategy for the design of high-performance cathode.