In-situ electrodeposited MnO2/Mn3O4 heterostructured cathode for high-performance aqueous zinc-ion batteries

Manganese-based oxides are recognized as promising cathode materials for aqueous zinc-ion batteries (AZIBs), owing to their high operating voltage, desirable specific capacity, and abundant elemental reserves. However, sluggish electrochemical reaction kinetics and severe structural degradation of single-phase manganese oxides during long-term charge-discharge cycles significantly impair their cycling stability and rate capability, impeding their large-scale industrial application. In this work, a MnO 2 /Mn 3 O 4 heterostructured composite cathode was successfully synthesized via a facile in-situ electrodeposition method. The unique composition and heterostructure endow the MnO 2 /Mn 3 O 4 composite with abundant active sites, enhanced electrical conductivity, and excellent structural stability. Benefiting from these advantages, the MnO 2 /Mn 3 O 4 composite cathode delivers a high initial specific discharge capacity of 384 mAh g −1 at 0.1 A g −1 , outstanding rate performance with a reversible capacity of 197 mAh g −1 at 2 A g −1 , and ultra-long cycling stability with 95.4% capacity retention after 5000 cycles, which is substantially superior to that of pure MnO 2 and pure Mn 3 O 4 control samples. This work demonstrates a facile and efficient strategy for the design and fabrication of high-performance multiphase manganese-based composite cathodes for next-generation AZIBs.