Emerging Conversion Chemistry for High-Energy Electrolytic Zinc–Manganese Batteries: Beyond Intercalation

Aqueous zinc-manganese batteries (ZMBs) represent a compelling solution for grid-scale energy storage due to their low cost, inherent safety, and ease of manufacturing. However, conventional ion-intercalation ZMBs (IZMBs) are often hindered by bottlenecks such as limited energy density and poor cycling stability. Recently, electrolytic ZMBs (EZMBs), based on the two-electron Mn2+/MnO2 deposition-dissolution chemistry, have emerged with high operating voltages (∼1.99 V) and exceptional theoretical capacities (616 mAh g-1), paving a new way for performance breakthroughs in high-energy aqueous batteries. This review provides a deep dive into the mechanistic divergence between IZMBs and EZMBs, clarifying the core significance of EZMBs in enhancing energy density, longevity, and cost efficiency. By deconstructing critical challenges across cathode conversion, zinc anode interfaces, and electrolyte environments, we synthesize recent breakthroughs in cathode modification, anode protection, and electrolyte engineering to establish a unified design framework for high-performance EZMBs. Furthermore, this review identifies emerging opportunities and future research directions, aiming to provide systematic theoretical guidance and design inspiration for the development of next-generation, high-energy-density, and long-life EZMBs.