Ultrasound assisted formation of Mn₂SnO₄ nanocube as electrodes for high performance symmetrical hybrid supercapacitors

In this work, we have synthesized Mn₂SnO₄ material with nanocube morphology from MnSn(OH)₆ intermediate via a simple one-pot sonochemical synthesis. The structural and morphological studies of the material were characterized by X-ray diffraction (XRD) and field emission scanning electron microscopy (FE-SEM). The Mn₂SnO₄ nanocubes were used as the active electrode material for supercapacitor applications. It delivered a maximum specific capacitance of 298 F g^-1 at a current density of 1 mA cm⁻². The Mn₂SnO₄ nanocubes showed excellent cycle stability with capacitance retention of 89% over 5000 cycles and desirable rate capability retain 223 F g^-1 at a current density of 15 mA cm⁻² in a three electrode system. Further, these materials were applied to the symmetric supercapacitor device, and it exhibited high specific capacitance (144 F g^-1 at 3 mA cm⁻²), good cycle stability (75% capacitance retention after 1000 cycles), high energy density (30.4 Wh kg⁻¹) and power density (7.9 kW kg^-1 at 26.4 Wh kg⁻¹) in a potential range of 2 V in 1 M Na₂SO₄ aqueous electrolyte. These results suggest that Mn₂SnO₄ nanocubes show suitable electrode material for high-performance supercapacitor applications.