Micro/nano blocks of Ni/MnO composites synthesized by microwave-assisted solvothermal for supercapacitors

The micro/nano blocks of Ni/MnO composites were synthesized by a facile microwave-assisted solvothermal method. The results indicated that the morphology changed from irregular block to polyhedron and then to the sphere with the increase of ethylene glycol (EG) ratio in the solvent. The results indicated the specific capacitance of the obtained material increased as the EG ratio increased, but when the EG ratio exceeded 60%, the change of specific capacitance was not obvious (less than 5%). For the Ni/MnO material synthesized in pure EG, its specific capacitance reached 860 F/g at 1 A/g and the capacitance retention maintained 58% after 6500 cycles. The micro/nano structure of Ni/MnO material formed in EG solvent increased the surface area and provided more transfer channels for the electrolyte ion, which were all beneficial to improve the electrochemical properties. The high capacitance and good cycle stability especially after a period of cycles demonstrated the obtained Ni/MnO materials had a potential application for the supercapacitor electrode material.