Structure and Stoichiometry of Nickel Hydroxides in Sintered Nickel Positive Electrodes

Differential thermal analysis (DTA) is shown to be a powerful tool in the study of the structure of electrochemically active materials. DTA was combined with chemical and x‐ray diffraction analysis to follow both the electrolytic development in solutions and the thermal decomposition of the charged state of sintered nickel electrodes impregnated with nickel hydroxide. The charged state contains active oxygen, insoluble potassium, water of constitution, and water of hydration. The electrochemical capacity is close to the electrochemical equivalent of the active oxygen formed on charging. The layer lattice is distorted and decomposes exothermically to when heated above 100°C.