Interlayer spacing engineering in N doped MoS2 for efficient lithium ion storage

Highlights: • MoS₂ with enlarged interlayer spacing were synthesized. • Few-layered MoS₂ nanosheets grow vertically on GO sheets. • N plasma treatment is applied on GO/ISE-MoS₂ composites. • N has been uniformly doped into both rGO and MoS₂. • N-rGO/ISE-MoS₂ exhibits excellent reversible and rate capacity. MoS₂ has been intensively studied as a promising anode material for high capacity lithium ion batteries (LIBs), which is strongly limited by its poor cycling stability and inferior rate performance. In this work, the strategy of interlayer spacing engineering is applied on MoS₂ to effectively expand the interlayer spacing from 0.62 nm to 0.98 nm, with the addition of -cysteine during hydrothermal process. The cycling stability is significantly improved. The composites of interlayer expanded MoS₂ and graphene oxide are further treated by N plasma to effectively dope N into both reduce graphene oxide and MoS₂. The final product exhibits outstanding electrochemical performance as anode in LIBs, with high reversible capacity of 643 mA h·g⁻¹ after 400 cycles at the rate of 500 mA g⁻¹ and excellent rate capacity of 580 mA h·g⁻¹ up to the rate of 2000 mA g⁻¹. This work demonstrates that proper nanostructure engineering and electronic structure modification can make MoS₂ a promising electrode material in highly fast and stable energy storage applications.