Construction of an MoSe2/MoS2 nanosheet heterostructure for enhanced sodium storage performance

Abstract

Transitional metal dichalcogenides represented by MoS₂ have displayed great promise as anode materials for sodium-ion batteries owing to their high theoretical capacities and excellent redox reversibilities. However, they usually suffer from large volume variations and sluggish reaction kinetics, resulting in an unsatisfactory sodium storage performance, impeding their practical applications. Herein, an MoSe₂/MoS₂ heterostructure composed of ultrasmall MoSe₂ nanosheets embedded in MoS₂ nanosheets was designed and prepared via a simple hydrothermal process. The MoSe₂/MoS₂ heterostructure consisted of ultrasmall MoSe₂ nanosheets embedded between the voids of MoS₂ nanosheets, which could confine the size of the nanosheets, shortening the ion diffusion path and promoting charge transfer. Furthermore, this heterostructure possessed rich well-matched heterointerfaces between MoS₂ and MoSe₂, which could effectively prevent heterointerface separation, accommodate volume changes, maintain the structural stability, accelerate charge transport and enhance the reaction kinetics. When applied as an anode material for sodium-ion batteries, the MoSe₂/MoS₂ heterostructure presented an excellent cycling performance with a high specific capacity of 462.3 mA h g⁻¹ at 1 A g⁻¹ and superior rate performance of 314.3 mA h g⁻¹ at 10 A g⁻¹. The all-Mo-based sulfide heterostructure may provide a reference for designing high-performance bimetallic sulfide anode materials for sodium-ion batteries.