The relation between the structure and the stability at a low potential was investigated for the cobalt oxyhydroxide/CeO2 composite samples as additives for the nickel hydroxide electrode. The structural analysis of the samples was done by high-energy synchrotron X-ray diffraction (XRD), X-ray absorption fine structure (XAFS) and transmission electron microscopy (TEM) analyzes. The samples were a mixed phase of the cobalt oxyhydroxide and CeO2 phases. There are some tendencies that the stability at -1.0 V(vs. Hg/HgO) increased with an increase in the phase abundance of the CeO2 phase. The oxidation state of the samples in the range of the Ce/(Ce+Co) ratio = 0.3 and 0.4 was almost identical to that for the cobalt oxyhydroxide and in a good relation with the resistivity values. The resistivity was significantly increased above the Ce/(Ce+Co) ratio = 0.5. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.072212jes] All rights reserved.