positive electrodes with 2,3-butanedione and with tetrabutyl ammonium bifluoride as model leaching agents. In the bifluoride trials, it was found that [Ni] in the leachate was proportional to X Co (X Ni ) 3 , where X M is the ideal stoichiometry in the bulk oxide, and inversely proportional to (X Mn ) 2 ; [Mn] to X Co (X Ni ); and [Co] to X Co . The relationships between metal concentrations and stoichiometry may indicate that nickel, as a next-nearest neighbor on the positive electrode surface, can make dissolution more favorable in some instances.