Nanostructured (Co, Mn)(3)O(4) for High Capacitive Supercapacitor Applications

Nanostructured Co doped Mn(3)O(4) spinel structure ((Co, Mn)(3)O(4)) were prepared by co-precipitation under O(3) oxidizing conditions and post-heat treatment. The product was composed of nanogranules with a diameter of 20–60 nm. The electrochemical performance of (Co, Mn)(3)O(4) electrode was tested by cyclic voltammetry, impedance, and galvanostatic charge-discharge measurements. A maximum specific capacitance value of 2701.0 F g(−1) at a current density of 5 A g(−1) could be obtained within the potential range from 0.01 to 0.55 V versus Hg/HgO electrode in 6 mol L(−1) KOH electrolyte. When at high current density of 30 A g(−1), the capacitance is 1537.2 F g(−1) or 56.9% of the specific capacitance at 5 A g(−1), indicating its good rate capability. After 500 cycles at 20 A g(−1), the specific capacitance remains 1324 F g(−1) with a capacitance retention of 76.4%.