Heterointerface Engineering‐Induced Oxygen Defects for the Manganese Dissolution Inhibition in Aqueous Zinc Ion Batteries

Manganese‐based material is a prospective cathode material for aqueous zinc ion batteries (ZIBs) by virtue of its high theoretical capacity, high operating voltage, and low price. However, the manganese dissolution during the electrochemical reaction causes its electrochemical cycling stability to be undesirable. In this work, heterointerface engineering‐induced oxygen defects are introduced into heterostructure MnO 2 (δa‐MnO 2 ) by in situ electrochemical activation to inhibit manganese dissolution for aqueous zinc ion batteries. Meanwhile, the heterointerface between the disordered amorphous and the crystalline MnO 2 of δa‐MnO 2 is decisive for the formation of oxygen defects. And the experimental results indicate that the manganese dissolution of δa‐MnO 2 is considerably inhibited during the charge/discharge cycle. Theoretical analysis indicates that the oxygen defect regulates the electronic and band structure and the Mn‐O bonding state of the electrode material, thereby promoting electron transport kinetics as well as inhibiting Mn dissolution. Consequently, the capacity of δa‐MnO 2 does not degrade after 100 cycles at a current density of 0.5 A g −1 and also 91% capacity retention after 500 cycles at 1 A g −1 . This study provides a promising insight into the development of high‐performance manganese‐based cathode materials through a facile and low‐cost strategy.