The Dissolution Kinetics of Lithiated NiO in Aqueous Acid Solutions.

摘要

The factors controlling the dissolution of metal oxides are of major importance in understanding the role of such oxides in the control of corrosion through the formation of passivation films and the use of various oxides as battery cathodes. The dissolution kinetics of mosaic lithiated nickel oxide have been examined in concentrated H2SO4and HCl solutions as a function of potential and found to be strongly dependent on potential with the rate increasing with increasingly anodic potentials and passing through a maximum in the H2SO4solutions. The temperature dependence indicates Arrhenius behavior with an enthalpy of activation of 23kcal/mole. Complexing agents such as EDTA have been found to increase the dissolution rate. At relatively anodic potentials, O18labelling experiments indicate that the generation of O2involves to a significant extent lattice O(-2),probably through a mechanism involving the p-carriers falling into O(-2) surface states.