Urchin-like Ni(OH) 2 –Co(OH) 2 hollow microspheres were successfully synthesized by a microwave-incorporated hydrothermal method. The Ni(OH) 2 –Co(OH) 2 hollow microspheres achieved a high specific capacitance of 2164 F g −1 at 1 A g −1 and long-term cycle life. Electrochemical data reveal that the Ni(OH) 2 –Co(OH) 2 hollow microspheres exhibits much better electrochemical reversibility and specific capacitance retention than that of the single Ni(OH) 2 or Co(OH) 2 based on peak potential difference, symmetry of charge–discharge curves, and specific capacitances at high charge–discharge rates. Furthermore, the designed Ni(OH) 2 –Co(OH) 2 /graphene asymmetric supercapacitor displays good reversibility and a high specific capacitance of 169 F g −1 at 1 A g −1 , 145 F g −1 at 3 A g −1 , and 116 F g −1 at 5 A g −1 , indicating a good ability to deliver a high energy density at a high power density. These results proved that the Ni(OH) 2 –Co(OH) 2 hollow microspheres can be promising electroactive materials for supercapacitor and the microwave-incorporated hydrothermal method provided a one-step, template-free, and cost-effective route for fabricating pseudocapacitive materials in 3-D form.
