MoS2 encapsulated in three-dimensional hollow carbon frameworks for stable anode of sodium ion batteries

Abstract

MoS₂ is an anode material that has produced high expectations in sodium ion batteries, mainly due to its layered structure and high theoretical specific capacity. However, it faces drastic volume changes during the ion insertion/extraction process, which restricts its electrochemical performance. Therefore, improving the structural stability and electrical conductivity of MoS₂ is a key issue to promote the potential application. Herein, a nitrogen-doped three-dimensional (3D) hollow carbon framework is designed to wrap MoS₂ in the holes to improve the stability of the structure and expose more active sites by a sequential freeze-drying, carbonization, and hydrothermal reaction method. The MoS₂ encapsulated in the 3D hollow carbon framework assembled half-cell exhibits a high capacity of 413.3 mA h g⁻¹ at 0.1 A g⁻¹ for 100 cycles and excellent stability at a high rate of 225.2 mA h g⁻¹ at 2 A g⁻¹ for 400 cycles. The improved conductivity and stability from the 3D hollow carbon frameworks justify the excellent sodium ion storage performance.