Charged-optimized ZnO/ ZnV2O4 composite hollow microspheres robust zinc-ion storage capacity

Lack of suitable cathode materials is one of the critical factors that hinder the advancement of aqueous zinc-ion batteries (AZIBs). Although low valent vanadium-based materials as zinc-ion host have high theoretical capacity, ineffectively discharge limits its application for AZIBs owning to the inherently unsuitable structure and physicochemical performance. Therefore, a ZnO/ZnV2O4 composite hollow microsphere (ZVO-3) was fabricated via a facile free-template solvothermal method and assembled as a cathode for AZIBs. When a first charge strategy is adopted, the ZVO-3 cathode exhibits approximately an initial columbic efficiency of 97%, high-rate capacity (93.3 mAh g(-1) at 8.0 A g(-1)), superior cycling ability (338 mAh g(-1) at 0.1 A g(-1), a capacity retention of 70% after 50 cycles) and excellent long-term cycling performance. Furthermore, the results of electrochemical dynamics indicate that the pseudo-capacitance dominated electrode reaction process with fast diffusion efficiency. This work not only exploits a method for designing hollow structures of ZVO-3, but also shed lights on the application of charged-optimized low valent vanadium-based cathode for AZIBs or other multivalent-ion batteries.

Automated summary

The lack of suitable cathode materials has been a critical factor hindering the development of aqueous zinc-ion batteries (AZIBs). This study successfully designed and fabricated ZnO/ZnV2O4 composite hollow microspheres as cathode materials for AZIBs, demonstrating excellent performance and providing a new direction for the application of low valent vanadium-based materials in multivalent-ion batteries.