Enhanced kinetic behaviors of hollow MoO/MoS nanospheres for sodium-ion-based energy storage.

Mo-based heterostructures offer a new strategy to improve the electronics/ion transport and diffusion kinetics of the anode materials for sodium-ion batteries (SIBs). MoO/MoS hollow nanospheres have been successfully designed via in-situ ion exchange technology with the spherical coordination compound Mo-glycerates (MoG). The structural evolution processes of pure MoO, MoO/MoS, and pure MoS materials have been investigated, illustrating that the structureofthenanospherecan be maintained by introducing the S-Mo-S bond. Based on the high conductivity of MoO, the layered structure of MoS and the synergistic effect between components, as-obtained MoO/MoS hollow nanospheres display enhanced electrochemical kinetic behaviors for SIBs. The MoO/MoS hollow nanospheres achieve a rate performance with 72% capacity retention at a current of 3200 mA g compared to 100 mA g. The capacity can be restored to the initial capacity after a current returns to 100 mA g, while the capacity fading of pure MoS is up to 24%. Moreover, the MoO/MoS hollow nanospheres also exhibit cycling stability, maintaining a stable capacity of 455.4 mAh g after 100 cycles at a current of 100 mA g. In this work, the design strategy for the hollow composite structure provides insight into the preparation of energy storage materials.