A New High-Performance Porous Carbon-Coated Mn₃O₄/Na₂CO₃ Cathode for Suppressing Mn²⁺Dissolution in Aqueous Zinc Ion Batteries

Manganous-manganic oxide (Mn₃O₄), akin to other manganese-based oxides, faces several critical challenges such as substantial capacity fading and limited rate performance due to its inferior electrical conductivity, in addition to the inevitable dissociation of Mn²⁺. To address these issues, we introduce for the first time a novel carbon-coated Mn₃O₄/Na₂CO₃ (Mn₃O₄/Na₂CO₃/C) composite material. Comprehensive characterizations indicate that Na₂CO₃ effectively curtails Mn²⁺dissolution, enhances carbon encapsulation throughout charging/discharging cycles, and exposes additional active sites on the Mn₃O₄/Na₂CO₃/C composite. Electrochemical assessments confirm that the Mn₃O₄/Na₂CO₃/C-2 cathode exhibits exceptional electrochemical performance, outperforming other cathodes in the ZnSO₄ system. Moreover, the Mn₃O₄/Na₂CO₃/C-2 cathode delivers a high specific capacity of ~550 mAh g^M−1 at 0.1 A g⁻¹ and maintains a significant capacity of ~230 mAh g⁻¹ after 360 cycles at 1.0 A g⁻¹ within the 2.0 M ZnSO₄+0.2 M MnSO₄ electrolyte system, demonstrating its potential as a high-performance cathode material for aqueous zinc-ion batteries.