Structural evolution of vertically oriented graphene nanosheet templating Ni-Co hydroxide as pseudocapacitive electrode

High-performance pseudocapacitive electrode with vertically oriented graphene nanosheet (GN) templating Ni-Co hydroxide (NCH) is fabricated through a facial electrodeposition way. The structural evolution of electrodes after cyclic voltammetry treatment at different scan rates (from 5 to 500 mV s(-1)) and its impact on the electrodes' electrochemical performance are for the first time systematically investigated. The results reveal that the NCH/GN hybrid electrode exhibits ultrahigh electrochemical stability that the electrochemical properties of hybrid electrodes are not affected by the different rate-scanning treatments. GN grown on carbon cloth (CC) as nanotemplate for NCH pseudocapacitive material creates a rapid channel for ion/charge transfer between the electrolyte and electrode, and the robust interfacial bonding of hybrid structure is prerequisite for the high performance stability. Furthermore, asymmetric supercapacitor devices consisting of NCH/GN/CC as positive electrode and GN/CC as negative electrode were fabricated and electrochemically treated as well, further demonstrating the ultrahigh electrochemical stability of such NCH/GN/CC hybrid structures at various scan rates.