Capacitive Properties of Mesoporous Mn-Co Oxide Derived from a Mixed Oxalate

A mesoporous Mn-Co oxide for supercapacitors was derived from a mixed oxalate Mn0.8Co0.2C2O4nH2O, which was synthesized by a solid-state coordination reaction at room temperature. The synthesized mixed Mn-Co oxalate was decomposed in air at 250 ̊C, resulting in a tetragonal spinel Mn-Co oxide with a primary particle size less than 100 nm. The obtained Mn-Co oxide presents a mesoporous texture with a specific surface area of 120 m·g. Electrochemical properties of the Mn-Co oxide electrode were investigated by cyclic voltammetry and galvanostatic charge/discharge in 6 mol·L KOH electrolyte. The Mn-Co oxide electrode delivered specific capacitances of 383 and 225 F·g at scan rates of 2 and 50 mV·s, respectively. Subjected to 500 cycles at a current density of 1.34 A·g, the symmetrical Mn-Co oxide capacitor showed specific capacitance of 179 F·g, still retaining ~85% of its initial capacitance. The obtained Mn-Co oxide material showed good capacitive performance, which was promising for supercapacitor applications.