Synthesis and Electrochemical Property of CuO-Containing Li2MnO3

INTORDUCTION Li2MnO3-based positive electrodes for Li-ion batteries are promising material to obtain a large capacity because of high Li content. In order to induce the electrochemical activity of Li2MnO3, various ways have been attempted, mainly by substitution of other transition metals such as Ni or Co. Recently, we have reported a new way to enhance the electrochemical activity of Li2MnO3[1]. The material was composed of Li2MnO3 and CuO phases. The particle size of the former was much smaller than that of the latter by using TEM observation equipped with EDX. The specific charge and discharge capacity significantly increased with the content of CuO, while maintaining the electrochemical characters of Li2MnO3 itself. Coexisting with CuO produced nano-sized Li2MnO3 particles and depressed the kinetic barrier of the electrode reaction of Li2MnO3. We have no information on the reason why CuO can work like such a catalyst in the presence of Li2MnO3. Therefore, we prepared the precursors under the different pH condition during coprecipitation process and then investigated the relationship between the particle size and electrochemical property of CuO-containing Li2MnO3 as a positive electrode.