Versatile Preparation of Mesoporous Single-Layered Transition-Metal Sulfide/Carbon Composites for Enhanced Sodium Storage.

Abstract

Transition-metal sulfides are promising electrochemical energy storage materials due to their abundant active sites, large interlayer space, and high theoretical capacities, especially for sodium storage. However, the low conductivity and poor cycling stability at high current densities hamper their applications. Herein, a versatile dual-template method is reported to elaborate ordered mesoporous single-layered MoS₂ /carbon composite with high specific area, uniform pore size, and large pore volume. The single-layered MoS₂ is confined in the carbon matrix. The mesopores between the composite nanorods provide fast electrolyte diffusion. The obtained nanocomposite shows a high sodium-storage capability, excellent rate capacity, and very good cycling performance. A capacity of 310 mAh g^-1 can remain at 5.0 A g^-1 after 2500 cycles. Furthermore, a sodium-ion battery (SIB) full cell composed of the MoS₂ /carbon composite anode and a Na₃ V₂ (PO₄ )₃ (NVP) cathode maintains a specific capacity of 330 mAh g^-1 at 1.0 A g^-1 during 100 cycles. The mechanism is investigated by in situ and ex situ characterizations as well as density functional theory (DFT) calculations.