Cross-Doped Mn/Mo Oxides with Core-Shell Structures Designed by a Self-Template Strategy for Durable Aqueous Zinc-Ion Batteries

Manganese oxide as the star cathode material of aqueous zinc ion batteries is vigorously developed because of its environmental protection, outstanding theoretical capacity, and high voltage. However, severe Jahn–Teller distortion of trivalent Mn has detrimental effect on cyclic stability. Herein, 1D core-shell bimetal oxide with cross-doping of heteroatom is successfully designed by self-template method via one-step hydrothermal reaction. Specifically, the thick shell of Mo-doped α-MnO₂ with increased nanopores, expanded lattice spacing, and high oxidation state not only contributes high capacity but also suppresses the lattice distortion due to the doping of high-valent Mo⁶⁺; While the thin core of Mn-doped MoO₃ nanobelt supplies a shaped template, important Mo source, and improved conductive path. Therefore, this composite exhibits a superior capacity of 366.2 mAh g⁻¹ at 0.2 A g⁻¹ and 100% capacity retention after 100 cycles, which effectively increases to 4.1 times from 1.5 times of pure α-MnO₂ based battery. Besides promoting the electrochemical performance in coin-cell batteries, composite materials also balance the electrochemical and mechanical performances in flexible micro-batteries with area energy density of 261.2 µWh cm⁻². Therefore, this synergetic self-template and cross-doping strategy can extend to the material design of other high-performance metal oxides for energy storage application.