Hierarchical manganese valence gradient MnO2via phosphorus doping for cathode materials with improved stability

Abstract

The search for a method for enhancing the electrochemical performance of manganese dioxide is still a challenge. Herein, we report a rod-like P-MnO_x cathode material with a hierarchical manganese gradient valence through the phosphatization process. For the incorporation of P, Mn₃O₄ was formed on the surface of MnO₂ and exhibited a gradient valence structure, while the oxygen defect concentration in P-MnO_x increased. The unique structure was verified via XRD, TEM and XPS. As the cathode material for a supercapacitor, the specific capacitance of P-MnO_x was 126.3 F g⁻¹, which was four times that of MnO₂. The assembling of the coin cells of aqueous ZIBs with P-MnO_x also showed good rate performance. The electrochemical performance of the synthesised P-MnO_x cathode was enhanced for the synergistic effect of improved conductivity and structural stability.