Carbon encapsulated nanosheet-assembled MoS2 nanospheres with highly reversible lithium storage

Abstract

Carbon encapsulated nanosheet-assembled MoS2 (C@MoS2) nanospheres have been synthesized using poly(vinylpyrrolidone) (PVP) as surfactant and carbon source via hydrothermal approach in combination with high-temperature calcination process. PVP plays an important role in the formation of nanosheet-assembled MoS2 nanospheres, which can be in-situ converted into amorphous carbon to encapsulate MoS2. When evaluated for electrochemical lithium storage properties, the C@MoS2 nanospheres exhibit enhanced electrochemical energy storage performances compared to the bare MoS2 nanosheets, including high specific capacity (1135.8mAhg−1 at 0.1Ag−1), excellent rate capability (384.4mAhg−1 at 8Ag−1 and 330.5mAhg−1 at 10Ag−1), and good cycling stability (97.03% capacity retention after 100 cycles at 0.5Ag−1). The enhanced lithium storage performances of the C@MoS2 nanospheres can be ascribed to the boosted electronic conductivity arising from PVP derived carbon, and the facilitated lithium ion transport due to the shorter diffusion length of MoS2 nanosheet-assembled structures.