Hierarchical self-supported Ni(OH)2@Ni12P5 for supercapacitor electrodes with ultra-high area ratio capacitance

Transition metal hydroxides, due to their low cost and high theoretical capacity, are promising candidates for supercapacitors . However, the lower conductivity of hydroxides usually results in devices exhibiting poor specific capacity. Here, Ni(OH) 2 @Ni 12 P 5 electrodes are designed and prepared, showing great potential for applications. This composite electrode, prepared by simple phosphating treatment and electrodeposition . Compared with the Ni(OH) 2 prepared by direct deposition, this rationally designed electrode exhibits more excellent electrochemical properties. The prepared Ni(OH) 2 @Ni 12 P 5 electrode exhibits a good area specific capacitance of 15.89 F•cm −2 at a current density of 10 mA•cm −2 , which is 2.93 times higher than that of the Ni(OH) 2 electrode (5.43 F•cm −2 ). In addition, the assembled Ni(OH) 2 @Ni 12 P 5 //AC asymmetric supercapacitor exhibits an energy density of 0.38 mWh•cm −2 at a power density of 8.00 mW•cm −2 . Therefore, this work provides a new strategy for the synthesis of high-performance supercapacitor electrodes.