Porous Mn₂O₃@C Cathode With High Activity and Long Lifespan for Aqueous Zinc Ion Batteries

Manganese-based oxides are widely employed as cathode materials for aqueous zinc ion batteries (AZIBs) due to their low toxicity and high theoretical specific capacity. However, their inherent poor electrical conductivity, coupled with the dissolution of manganese into the electrolyte, often leads to structural degradation of the cathode. To address these challenges, Mn-MOF was utilized as a precursor to synthesize a corncob popcorn-like Mn₂O₃@C composite with high activity and long lifespan for AZIBs. This distinctive porous carbon encapsulation architecture leverages oxygen vacancies to modulate the spacing of Mn metal oxide layers and alter the valence states of metal ions, thereby enhancing both structural stability and conductivity, and reducing the Zn²⁺ diffusion path. The porous structure also improves the wettability of the electrode surface and electrolyte penetration, and provides ample and rapid ion transport channels. Consequently, the fabricated corncob popcorn-like Mn₂O₃@C exhibits an outstanding specific capacity of 570.5 mA h g⁻¹ at 0.1 A g⁻¹ and a capacity retention of over 95% after 3000 cycles at 1 A g⁻¹. The Zn²⁺ storage mechanism was elucidated through various ex situ characterizations, revealing that the storage mechanism is governed by a mixed H⁺/Zn²⁺ co-insertion/de-insertion process. © 2025 The Author(s).