MnO₂ depositing on the surface of hollow porous carbon microspheres for supercapacitor application

A supercapacitor electrode material was synthesized by using hollow carbon spheres prepared via high temperature sintering of dopamine hydrochloride and subsequent coating with MnO₂. SEM, TEM and analysis of energy pattern were used to characterize the structure, morphology and elemental composition of the material, which proved that the material had a good hollow structure and uniform surface morphology, and that MnO₂ was successfully coated on the surface of the carbon material. Electrochemical characterization using charge-discharge cycles at constant current and other methods show that the prepared materials have good specific capacitance and cycle stability, and have a specific capacitance of 198 F.g⁻¹ at a current of 1 A·g⁻¹. When the charge and discharge cycle is carried out at 10 A·g⁻¹ for 5000 cycles, the capacitance remains stable at more than 180 F·g⁻¹.