Hybrid graphene@MoS2@TiO2 microspheres for use as a high performance negative electrode material for lithium ion batteries

Abstract

A graphene@MoS₂@TiO₂ hybrid material was successfully prepared by a multi-step solution chemistry method. Few-layered MoS₂ nanosheets were impregnated into the nanovoids of mesoporous TiO₂ microspheres and the composite was further encapsulated by a graphene layer. When used as a negative electrode material for lithium ion batteries, the nanovoids of TiO₂ reduced aggregation of MoS₂ and suppressed the large volume change of the active material. Moreover, the dissolution and shuttle of polysulfides were effectively suppressed by the hybrid bonding between MoS₂ and TiO₂. The nano-sized MoS₂ and TiO₂ particles encapsulated by a high electronic conductive graphene layer improved the charge transfer reaction of the electrode. Due to these merits, the graphene@MoS₂@TiO₂ showed a large discharge capacity of 980 mA h g⁻¹ at 0.1 A g⁻¹ current density with a capacity retention of 89% after 200 cycles. Moreover, the material delivered 602 mA h g⁻¹ at 2 A g⁻¹ current density, much larger than 91 mA h g⁻¹ for the pristine MoS₂. This demonstrated that the hybrid graphene@MoS₂@TiO₂ microspheres have great potential as a high-performance negative electrode material for lithium ion batteries.