In Situ X‐Ray Absorption Spectroscopic Studies of Nickel Oxide Electrodes

In situ transmission x‐ray absorption spectroscopy was used to investigate changes in the structure of as it was cycled as a nonsintered nickel oxide electrode in concentrated alkali. Results were obtained for dry as‐prepared electrodes and electrodes that were charged or discharged. Changes were observed in the (0001) plane of the as a function of cycling. In the charged material there was a contraction in the Ni‐O and Ni‐Ni distances. The EXAFS results and the XANES spectra strongly indicate that the Ni‐O coordination is symmetrical in , whereas the coordination is asymmetric in the charged material.