Developments of Advanced Cathodes and Stabilized Zinc Anodes for High-performance Aqueous Zinc-ion Batteries

Aqueous rechargeable zinc-ion batteries (ZIBs) have attracted considerable attention as one of the most promising energy storage systems for the grid-scale application owing to the natural merits of metallic Zn, including a high theoretical capacity, suitable redox potential, low cost, high safety, and eco-friendliness. However, the existing aqueous ZIBs are far from satisfying the requirements of practical applications. Significant challenges hindering the further development of ZIBs come from the low utilization and poor cycling stability of cathodes and limited reversibility of Zn anodes associated with dendrite growth, corrosion, and passivation. To date, enormous efforts have been devoted to developing high-performance cathode materials, reliable electrolytes, and stable Zn anodes to achieve ZIB with high energy and power densities and long cycle life. These progresses have been reviewed in this dissertation. Regarding the main issues of ZIBs, the dissertation covered both the cathode and anode to comprehensively improve the electrochemical performance of ZIBs. For the cathode, high-performance manganese oxide-based cathode materials have been developed by in-situ electrochemical activation of MnS, and rational design of hierarchical core-shell MnO2@carbon nanofiber structures. To further understand the underlying reasons for the enhanced electrochemical performance, the charge storage mechanisms of manganese oxide-based cathodes in ZIBs have been in-depth investigated. With respect to the Zn anode, a thin polyvinyl alcohol (PVA) coating layer on the Zn anode has enabled dendrite-free, long-life aqueous Zn batteries by effectively regulating the interfacial ion diffusion and inducing the homogeneous Zn nucleation and deposition of stacked plates with preferentially crystallographic orientation along (002)Zn planes. This work is expected to provide facile and low-cost approaches for developing high-performance, cost-effective, and stable aqueous ZIBs and shed light on a new mechanistic understanding of manganese oxide-based cathodes.