Regulation of the discharge reservoir of negative electrodes in Ni–MH batteries by using Ni(OH) (x= 2.10) and γ-CoOOH

Abstract

a b s t r a c tIn this paper, a novel strategy to regulate the discharge reservoir of negative electrodes in Ni-MH batteries is introduced by using Ni(OH) x (x = 2.10) and ␥-CoOOH. The electrochemical measurements of these batteries demonstrate that the use of Ni(OH) x (x = 2.10) and ␥-CoOOH can not only successfully regulate the discharge reservoir of negative electrodes in Ni-MH batteries to an adequate quantity, but also effectively improve the electrochemical performance of the batteries. Compared with normal batteries, the in-house prepared batteries with a lower discharge reservoir exhibit an enhanced discharge capacity, improved high-rate discharge ability, higher discharge potential plateau and superior cycle stability. The effect of Ni(OH) x (x = 2.10) and ␥-CoOOH on the electrochemical performance of nickel electrode is also investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The results suggest that the new method is simple and effective for cost reduction of Ni-MH batteries with improved electrochemical performance.

Isothermal decomposition kinetics of nickel (II) hydroxide powder

“…Oxides, hydroxides and oxyhydroxides of nickel are of interest as electrode materials for rechargeable batteries [1][2][3][4][5][6][7][8]. Nickel (II) hydroxide occurs in at least three polymorphs, α, β and γ, and transitions with nickel (III) oxyhydroxide in a redox reaction at battery electrodes during charging and discharging.…”

A comparative study of structural and electrochemical properties of high-density aluminum substituted α-nickel hydroxide containing different interlayer anions

“…the D 50 value of samples A, B, C, D and E are 25.38, 23.54,26.08, 24.47 and 23.92 mm, respectively, indicating that the effect of the anions on the particle size of a-Ni(OH) 2 is slight under the same preparation conditions. The tap-densities of samples A, B, C, D and E are 1.89, 1.63, 1.92, 1.56 and 1.88 g cm À3 , respectively, demonstrating that to some extent the interlayer anions affect the tapdensity of the end product.…”

“…Consequently, it is imperative to enhance the tap-density of Al-substituted a-Ni(OH) 2 for its practical use. In the previous work [25,26], we have studied the effect of tap-density on the electrochemical performance of non-spherical b-Ni(OH) 2 electrodes and found that better electrochemical activity can be achieved for non-spherical b-Ni(OH) 2 with a higher tapdensity. The high-density b-Ni(OH) 2 materials exhibit a dense solid microstructure, which contains many overlapped sheet nano crystalline grains, and have a high density of structural disorder and a large specific surface area, resulting in an enhanced electrochemical performance.…”

Degradation Factors and Durability of Large Scale Ni-metal Hydride Batteries

“…[4][5][6][7][8][9] Nickel hydroxide is used as the positive electrode material but features poor electrical conductivity after its reaction to form NiOOH in the charging process. Hence, conductive materials, [10][11][12][13][14] or Co compounds [15][16][17][18][19][20][21] are usually added to the positive electrodes and methods for introducing these additives and their influence on battery performance have been extensively studied. [22][23][24][25][26][27][28][29] There have been many reports on the degradation mechanism of nickel metal hydride batteries.…”