Insights on rational design and energy storage mechanism of Mn-based cathode materials towards high performance aqueous zinc-ion batteries

Benefiting from the low cost, high safety and environmentally friendly characteristics, aqueous second zinc ion batteries (AZIBs) have attracted wide attention. The electrochemical performance of the AZIBs is highly influenced by cathode materials. Mn-based compounds are deemed as promising cathode materials for AZIBs because of their various crystal structures and three-dimensional spatial frameworks. However, the diversity in crystal structure and chemical constituent for Mn-based compounds lead to a distinction of energy storage mechanisms, which engenders tremendous discrepancy in electrochemical properties. Herein, a state-of-the-art review of the rational construction of high-performance Mn-based cathodes of AZIBs is presented. Firstly, the energy storage mechanisms of Mn-based cathodes are systematically clarified. Accordingly, the reasonable strategies including morphology design, surface modification, defect engineering, structure modulation are comprehensively summarized. At last, the challenges, future developments, and prospects of Mn-based materials for AZIBs are prospected. This review provides an important understanding for the design and optimization of high-performance Mn-based cathodes materials, which can be expected to shed light on the future development of stable Mn-based cathodes toward high-performance AZIBs.