Enhanced kinetic behaviors of hollow MoO2/MoS2 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 2 /MoS 2 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 2 , MoO 2 /MoS 2 , and pure MoS 2 materials have been investigated, illustrating that the structure   of   the   nanosphere   can be maintained by introducing the S-Mo-S bond. Based on the high conductivity of MoO 2 , the layered structure of MoS 2 and the synergistic effect between components, as-obtained MoO 2 /MoS 2 hollow nanospheres display enhanced electrochemical kinetic behaviors for SIBs. The MoO 2 /MoS 2 hollow nanospheres achieve a rate performance with 72% capacity retention at a current of 3200 mA g −1 compared to 100 mA g −1 . The capacity can be restored to the initial capacity after a current returns to 100 mA g −1 , while the capacity fading of pure MoS 2 is up to 24%. Moreover, the MoO 2 /MoS 2 hollow nanospheres also exhibit cycling stability, maintaining a stable capacity of 455.4 mAh g −1 after 100 cycles at a current of 100 mA g −1 . In this work, the design strategy for the hollow composite structure provides insight into the preparation of energy storage materials.