Cathodic deposition of Ni(OH)2 and Co(OH)2 for asymmetric supercapacitors: Importance of the electrochemical reversibility of redox couples

► Reversibility of redox materials determines CS retention and energy capture efficiency of asymmetric ECs. ► CS of Ni(OH)2 and Co(OH)2 prepared by cathodic deposition are 2217 and 549 F g−1, respectively. ► Ni(OH)2-graphene is an energy-oriented EC of the asymmetric type. ► Co(OH)2-graphene is a power-oriented EC of the asymmetric type.