Abstract: The invention relates to lithiated cobalto-cobaltic oxides, especially stoichiometric Co.sub.3 O.sub.4, which have been found to be remarkably efficient electrocatalysts, especially at relatively high total lithium contents of more than 2 atom percent, preferably from 5 to 12 atom percent. The electrocatalysts are especially suitable for oxygen evolution and reduction electrodes and have been found to exhibit long term stability over periods up to 6,000 hours. They are also useful in purely chemical processes such as those involving a decomposition of hydrogen peroxide or peroxyl ions.