Enhancing Aqueous Zinc-Ion Battery Cathodes with Ce/Cu Codoping: PEO-Assisted Self-Assembly for Improved Performance

Zinc-ion batteries (ZIBs) have emerged as a promising battery technology due to their abundant resources, low cost, and high energy density. However, the performance of ZIBs still requires improvement to meet the practical demands of energy storage systems. This study proposes a plasma electrolytic oxidation (PEO)-assisted hydrothermal intercalation method for preparing aqueous zinc-ion battery cathode materials. Initially, titanium foil was treated with PEO to form a porous oxide layer, increasing the surface area and providing active sites. Subsequently, MnO2 was deposited via hydrothermal reaction with Ce and Cu ions incorporated to enhance its electrochemical performance. SEM, EDS, XRD, and XPS characterizations revealed that Ce and Cu doping expanded the interlayer spacing of the MnO2 lattice, increased the specific surface area, and introduced oxygen vacancies. The optimized PEO-MCC cathode delivered an initial discharge capacity of 98.44 mAh g–1, retaining 40 mAh g–1 after 2000 cycles along with improved charge transfer resistance and cycling stability. This study demonstrates that the PEO-assisted hydrothermal synthesis is an effective strategy for developing high-performance ZIBs cathodes, providing insights into the design and synthesis of next-generation energy storage systems.