Structural comparison of nickel electrodes and precursor phases

In this paper we summarize our previous Raman spectroscopic results and discuss important structural differences in the various phases of active mass and active mass precursors. Raman spectra provide unique signatures for these phases, and allow one to distinguish each phase, even when the compound is amorphous to X-rays (i.e., does not scatter X-rays because of a lack of order and/or small particle size). The structural changes incurred during formation, charge and discharge,d cobalt addition, and ageing will be discussed. The oxidation states and dopant contents are explained in terms of the nonstoichiometric structures.