Nano-bowl-like carbon confined 1T/2H-MoS2 hybrids as anode for high-performance sodium-ion storage

For sodium-ion batteries (SIB), MoS2 is considered as a promising anode material due to the suitable layer crystal structure and high theoretical capacity. However, the development of 2H-MoS2 is limited by the poor rate capability and bad cycling performance because of the low conductivity and the large change in volume. Here, a hybrid material (1T/2H-MoS2@HBC) is successfully synthesized, inwhich 1T/2H phases of MoS2 is researched as chief electrochemical active component, and hollow bowl-like carbon (HBC) is utilized as structural container to mitigate volume expansion and enhance electrical conductivity. The distinctive design of 1T/2H-MoS2@HBC contributes to the remarkable high reversible capacity (445 mAh g−1 at 1 A g−1) and the excellent rate performance (358 mAh g−1 at 5 A g−1). When the batteries are cycled for 2000 cycles, their discharge capacity remains at 349.3 mAh g−1. The coulomb efficiency close to 100 %, indicating excellent cyclic stability. Reaction kinetics are studied to verify the structure benefits of 1T/2H-MoS2@HBC. In addition, ex-situ and in-situ techniques are used to elucidate the reaction mechanism of 1T/2H-MoS2@HBC. Sodium-ion capacitor full cells are manufactured using the button cell architectures (1T/2H-MoS2@HBC||HBC), which offered long cycle life and comparatively low self-discharge rate. Based on the aforementioned results, 1T/2H-MoS2@HBC exhibits the potential for applications on sodium-ion energy conversion systems.