Construction of MoO₂ Quantum Dot–Graphene and MoS₂ Nanoparticle–Graphene Nanoarchitectures toward Ultrahigh Lithium Storage Capability

Herein, MoO 2 quantum dots (QDs; <5 nm) are synthesized through a one-step solvothermal process. MoO 2 QD-bonded graphene sheets (MoO 2 -QDs@RGO) are facilely produced and can be further converted through sulfidation into MoS 2 nanoparticle-bonded graphene sheets (MoS 2 -NPs@RGO). The novel MoO 2 -QDs@RGO electrodes demonstrate exceptionally attractive lithium storage capability (e.g., 1257 mA h g –1 at 100 mA g –1, being close to the highest values ever reported for a MoO 2 -based lithium ion battery electrode), rate capability, and cycle stability. Moreover, the MoS 2 -NPs@RGO delivered a superior capacity (1497 mA h g –1 at 100 mA g –1 ) with outstanding rate retention and cycling stability. The superior lithium storage capabilities are ascribed to the synergetic effects of the high-surface-area graphene sheets, the well-dispersed MoS 2 nanoparticles, and their strong bonding with each other, which effectively prevents aggregation of MoS 2 while the composite architecture allows fast transport of electrons and ions.