Advanced asymmetric supercapacitors based on Ni-3(PO4)(2)@GO and Fe2O3@GO electrodes with high specific capacitance and high energy density

Ni-3(PO4)(2)@GO composites were fabricated via a facile chemical precipitation method. More importantly, it was observed from electrochemical measurements that the obtained Ni-3(PO4)(2)@GO electrode showed a good specific capacitance (1392.59 F g(-1) at 0.5 A g(-1)) and cycling stability (1302 F g(-1) retained after 1000 cycles at 1 A g(-1)). In addition, a high-voltage asymmetric supercapacitor was successfully fabricated using Ni-3(PO4)(2)@GO and Fe2O3@GO as the positive and negative electrodes, respectively. The asymmetric supercapacitor could be cycled reversibly in the high-voltage region of 0-1.6 V and displayed intriguing performances with a maximum specific capacitance of 189 F g(-1) at a current density of 0.25 A g(-1). Furthermore, the Fe2O3@GO//Ni-3(PO4)(2)@GO asymmetric supercapacitor exhibited a high energy density of 67.2 W h kg(-1) and an excellent long cycle-life along with 88% specific capacitance retention after 1000 cycles. The impressive results presented here may pave the way for promising applications in high energy density storage systems.