Growing highly capacitive nano-Ni(OH) 2 on freshly cut graphite electrode by electrochemically enhanced self-assembly

Highly capacitive nano-Ni(OH) 2 spontaneously grows on the surface of a freshly cut graphite electrode (FGE) dipped in a NiCl 2 aqueous solution. The obtained nano-Ni(OH) 2 /FGE composite electrode, free of binders and other additives, shows a high specific capacitance of ~1850 F g −1 in 30 wt% KOH solution. Both capacity and cycling stability of the Ni(OH) 2 /FGE can be improved by electrochemical (cathodic) polarization enhanced self-assembling. The nano-Ni(OH) 2 was supposed to be self-assembled on FGE, where a doped nano-scale active water film incurs the formation of Ni(OH) 2. The results described here provide a facile and low-cost pathway to produce highly capacitive Ni(OH) 2 and Ni(OH) 2 /FGE composite electrode used for energy storage.