High-entropy doping strategy towards reinforced Mn-O bond for durable aqueous zinc ion batteries

Manganese-based cathode materials offer significant advantages in aqueous zinc ion batteries (ZIBs) due to their price, voltage, and capacity. Unfortunately, the notorious manganese dissolution leads to a significant impact on cycling stability. Although there are some measures to improve this problem, the strategy mainly focuses on protecting the material outside and cannot realize the limitation inside the material. To realize internal confinement and in-situ binding of manganese-based material, a high-entropy doped oxide Mn0.85Co0.03Fe0.03Ni0.03Cu0.03Cr0.03O/C (HE-MnO/C) with in-situ confinement was prepared by a high-entropy doping strategy and applied to ZIBs for the first time. It is demonstrated by combining theoretical calculations that due to the close arrangement of different metal atoms, the strong synergistic effect in the high-entropy material promotes a closer electron cloud overlap between manganese and oxygen, which further enhances the bonding strength of the Mn-O bond and limits the manganese dissolution. As a result, ultra-long cycle life and high cycling stability are realized by HE-MnO/C. An outstanding electrochemical performance is demonstrated by HE-MnO/C with a capacity retention of 93.2% after 10,000 cycles at 10 A g−1. This work provides new insights into solving the dissolution problem and further promotes the application of high-entropy materials in ZIBs.