Hierarchical porous honeycomb microspheres assembled by MoS₂ nanocrystals-embedded carbon nanosheets for high-performance lithium storage

Abstract

Hierarchical porous honeycomb microspheres assembled by MoS2 nanocrystals-embedded carbon nanosheets are synthesized by constructing polystyrene (PS) sphere-embedded Mo-polydopamine organic/inorganic hybrid microspheres, followed by carbonization and sulfuration. The as-prepared composite is systematically studied by various material characterization techniques. It is found that the diameters of the microspheres and honeycomb pores are 3–5 μm and 200 nm. The specific surface area reaches 150.8 m2 g−1. MoS2@honeycomb carbon microsphere anode can achieve outstanding rate performance (237 mAh g−1 at 10 A g−1), high specific capacity and stable long-term cycling performance (reversible capacity of 1199 mAh g−1 at 0.1 A g−1 after 120 cycles, 599 mAh g−1 at 2 A g−1 after 300 cycles with capacity decay rate of 0.07 % per cycle, 495 mAh g−1 at 5 A g−1 after 500 cycles). The high reversible capacity is mainly derived from conversion reaction of MoS2 and lithiation reaction of S, as revealed by the analyses on the rate discharge curves. Kinetic measurements and ex-situ characterization further demonstrate the fast and stable Li+ diffusion, low impedance, strong capacitive effect and robust composite structure. The assembled full cell exhibits a reversible capacity of 209.7 mAh g−1 after 1880 cycles at 5 A g−1 and can power a red LED lamp. Overall, the excellent lithium storage performance manifests the significant potential of this MoS2 composite in high-performance lithium-ion batteries.