Synthesis of Porous Pr-Fe@MnO ₂ as an Electroactive Material for Symmetric Supercapacitors

A mesoporous PR-Fe@MnO2 structure designed for high-performance supercapacitor was successfully prepared. The PR-Fe@MnO2 material, with conductive network structure, was constructed using a high temperature potassium ferrate (K2FeO4) and manganous acetate (Mn(CH3COO)2·4H2O) treatment process. During high-temperature carbonization, a portion of amorphous carbon generated a multi-layer graphene structure, causing PR-Fe@MnO2 to exhibit a high degree of graphitization. After doping, the transition metal Mn was investigated theoretically by performing density functional theory calculations. The results suggesting that doping of moderate Mn ions in the PR-Fe lattice improved the interactions between the OH− ions in the electrolyte and the Mn metal center, which also improved the electrical conductivity of the electrode. The Mn composition also increased the specific area for more electroactive sites and reduced the charge transfer resistance. As a result, PR-Fe@MnO2-1.5 had the highest specific capacitance of 601 F/g at 1.0 A/g and superior cycling stability with 97.8% capacitance retention after 10,000 cycles. Furthermore, the assembled PR-Fe@MnO2-1.5//PR-Fe@MnO2-1.5 symmetric supercapacitor provided a specific energy density of 25.7 Wh/kg at a power density of 384.9 W/kg. Thus, the excellent electrochemical performance of the PR-Fe@MnO2-1.5 composite makes it a promising electrode material for practical applications such as charge storage and in other pseudocapacitors.