Synthesis of Ni(OH)2, suitable for supercapacitor application, by the cold template homogeneous precipitation method

Abstract

α-Ni(OH)2 obtained by template homogeneous precipitation exhibits high electrochemical activity in supercapacitors. The main disadvantage is the high energy consumption for maintaining a high temperature during synthesis. To reduce energy consumption, it is proposed to lower the synthesis temperature. In the study, α-Ni(OH)2 was obtained by the method of cold template homogeneous precipitation using Culminal C8465 (0.5 %) as a template for 6 months at t=20–35 °С. The electrochemical characteristics of the sample were studied by cyclic voltammetry and galvanostatic charge-discharge cycling of a pasted binder-free electrode made without introducing an external binder in the supercapacitor mode. It was determined that low-crystalline α-Ni(OH)2 was formed, consisting of agglomerates of spherical particles. Low specific characteristics of nickel hydroxide were revealed at the beginning of cycling due to blocking of the active surface. It was shown that the specific capacity of the sample increased with further cycling due to the breakdown of aggregates into smaller particles; specific capacities of 80 F/g and 38 mA⋅h/g were obtained. However, the lack of binding properties of the template residues was revealed, resulting in a decrease in specific characteristics. It was concluded that it was necessary to introduce an external binder. A previously undescribed effect of a significant increase in the specific capacity during drying of an alkali-impregnated electrode caused by the disintegration of particle agglomerates during alkali carbonization (the maximum capacity is 135 F/g and 69 mA⋅h/g) was revealed. It was concluded that using the revealed effect of any nickel hydroxide samples obtained by various methods of bulk template synthesis was promising

Nickel Hydroxides: Requirements, Targeted Construction and Choice of Characteristics and Industrially Applicable Synthesis for Targeted Use in Electrochemical Devices

“…The main disadvantage of template synthesis is the need to remove the template, which can block part of the active surface of the particles. The influence of the amount of residual template on the specific capacity of hydroxide was researched [163] . It was shown that the residual amount of the Culminal C8465 template in the hydroxide particle can play the role of an internal binder in the preparation of the active mass.…”

“…The influence of the amount of residual template on the specific capacity of hydroxide was researched. [163] It was shown that the residual amount of the Culminal C8465 template in the hydroxide particle can play the role of an internal binder in the preparation of the active mass. This will allow the use of such nickel hydroxide for the manufacture of a binder-free electrode, reducing the cost due to the absence of rinsing of the hydroxide and the exclusion of the use of an external binder.…”

Definition of the role of polyvinyl alcohol during formation and in the structure of cathodic synthesized composite electrochromic nickel hydroxide layer: template or surfactant

“…In this case, a mixed PP-PVA matrix was formed. PVA was also successfully used to obtain nickel hydroxide (as a separate substance) by template electrochemical synthesis [49] and template homogeneous precipitation [50,51] (including low-and high-temperature ones [52]).…”

Sonochemical-Assisted Biogenic Synthesis of Theophrasite β-Ni(OH)2 Nanocluster Using Chia Seeds Extract: Characterization and Anticancer Activity

“…α-Ni(OH) 2 is stacked randomly along the axis (001) due to the presence of the anions between layers accompanied by water molecules, whereas the β-Ni(OH) 2 is perfectly stacked as hexagonal crystals. The morphological control for both morphologies of Ni(OH) 2 can be achieved by synthetic conditions as well as the incorporation of polymers or surfactants [ 16 ].…”