The supercapacitive performances of Co(OH)2/Ni(OH)2 composites in lithium hydroxide solution: Selection of electrolyte and effect of weight ratio

The supercapacitive performances of Co(OH)2/Ni(OH)2 composites in lithium hydroxide solution are investigated in detail. Cyclic voltammetries and galvanostatic charge/discharge measurements reveal that LiOH is the most suitable electrolyte for the composite electrodes among MOH (M = Li, Na and K). The redox behavior of the Co(OH)2/Ni(OH)2 composites different to that of the pure components shows that weight ratio of Co(OH)2/Ni(OH)2 exerts a great influence on the capacitive performances. After 1000 continuous charge/discharge cycles, the capacitance retention ratio for the composite electrode with the weight ratio of 2/3 is elevated from 41.6% to 88.2% compared with pure Ni(OH)2 electrode, exhibiting improved long-life cyclability.

► The supercapacitive performances of Co(OH)2/Ni(OH)2 composite electrodes were investigated in 1 M LiOH solution. ► The weight ratio in the Co(OH)2/Ni(OH)2 composite electrodes has great influence on their capacitive behavior. ► The capacitance retention ratio increases from 41.6% (pure Ni(OH)2 electrode) to 88.2% (Co(OH)2/Ni(OH)2 composite electrode with weight ratio of 2/3) after 1000 continuous charge/discharge cycles.