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

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.