Abstract:

Nickel hydroxide is widely used as an active material for hybrid supercapacitors. To improve the characteristics of supercapacitors, Ni(OH)2 with the optimal parameters to be determined should be synthesized. For this, Ni(OH)2 samples were prepared by various methods: decomposition, homogeneous precipitation, electrochemical synthesis using slit diaphragm electrolyzer under various current densities, with diaphragm or membrane, carbonate activation, immediate ultrasound post­treatment and an industrial sample, prepared by chemical route. Structural properties of the samples were studied by X­ray phase analysis, specific surface area – BET method by nitrogen adsorption, electrochemical characteristics – galvanostatic charge­discharge cycling in the supercapacitor mode. It has been demonstrated that high specific capacity is the most affected by α (or layered α+β) structure, optimal (average or low) crystallinity, introduction of activating additive and the ability of particle agglomerates to undergo breakdown into smaller particles during charge­discharge. Specific surface area has little influence on specific capacity. The sample prepared in slit diaphragm electrolyzer at 15.7 A/dm2 has a layered type of crystal structure, and the ability of particle agglomerates to undergo breakdown into smaller particles during charge­discharge, and showed the highest specific capacity of 650 F/g. Author Biographies Vadym Кovalenko, SHEI Ukrainian State University of Chemical Technology Gagarina ave., 8, Dnipro, Ukraine, 49005 FSBEI HE Vyatka State University Moskovskaya str., 36, Kirov, Russian Federation, 610000 PhD, associate professor Department of Analytical Chemistry and Food Additives and Cosmetics Department of Technologies of Inorganic Substances and Electrochemical Manufacturing

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