Self nickel hydroxides

However, it can undergo self-reductive dissolution (loss of active material) accompanied by oxygen evolution [349]. The active material of the positive electrode (in pocket plate cells) consists of nickel hydroxide mixed with small additions of cobalt and barium hydroxides to improve the capacity and charging/discharging performance and graphite to improve conductivity [348]. 

Cao, M., He, X., Chen,). and Hu, C. (2007) Self assembled nickel hydroxide three dimensional nanostructures A nanomaterial for alkaline rechargeable batteries. Crystal Growth Design, 7, 170-174. 

Abstract Self-assembly is an important phenomenon that leads to formation of interesting and novel structures in colloidal dispersions. We present experimental evidence for the existence of a cubatic phase in a colloidal dispersion of disc-like particles of nickel hydroxide colloidal dispersions. In this structure, disc-like particles self-assemble as domains of a few parallel discs and the orientation tends to be orthogonal in adjacent domains. This phase has been predicted previously by computer simulations. The domains are approximately equiaxial and are predicted to exist only within a limited range of aspect ratios and volume fractions. We have used the real space technique of cryo-transmission electron microscopy in our studies as this locally ordered structure could not be identified readily using scattering techniques, since the patterns are expected to be similar to those of isotropic liquid phases. 

Self-discharge means gradual loss of charge in the positive and/or negative electrode, when the battery is idle at open circuit. One reason can be the gradual reduction of the oxidation state in the positive electrode, e.g. the loss of oxygen in nickel hydroxide electrodes. 

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