Fabrication of inorganic@organic V2O5@PEDOT nanocomposite cathode for advanced aqueous manganese-ion batteries

Abstract

Aqueous manganese-ion batteries (AMIBs) show promise for energy storage because Mn anodes exhibit high capacity (976 mAh g⁻¹) and low potential (−1.18 V vs. SHE). However, cathode development faces challenges due to solvated Mn²⁺ with a large radius, resulting in slow ion diffusion, structural instability and limited capacity. Herein, we synthesized inorganic@organic V₂O₅@PEDOT nanocomposite via a facile in situ polymerization method by combining the EDOT monomer with V₂O₅. The resulting PEDOT coating exhibited strong adhesion to the V₂O₅ substrate owing to the redox reaction at the organic–inorganic interface, creating a unique hybrid architecture with enhanced charge transfer properties. Furthermore, the PEDOT composite significantly enhanced electrochemical performance by simultaneously suppressing vanadium dissolution and improving electronic conductivity, resulting in exceptionally high specific capacity (340.3 mAh g⁻¹ at 0.5 A g⁻¹) and rate capability (211.8 mAh g⁻¹ at 5 A g⁻¹). Systematic mechanism characterization confirmed the structural stability and high reversibility of Mn²⁺ insertion/extraction. The practical applicability of the nanocomposite was further demonstrated in a full-cell configuration (Mn‖V₂O₅@PEDOT), demonstrating high capacity. This study presents a high-performance cathode material for advanced AMIBs and provides new insights into design principles.