Preparation of mixed oxides Ca9Co12O28 and their electrochemical properties

Ca9Co12O28 nanoparticles with size of about 25 nm were prepared by Pechini process at 850 degrees C for 4 h. The as-obtained nanoparticles demonstrated initial charge/discharge capacities of 908 and 816 mAh/g and a stable discharge capacity of 210 mAh/g after 50 cycles. Different morphologies of Ca9Co12O28 as multilayer structure and micro-plates were also obtained by solid-state reaction and coprecipitation-precursor technique at 850 degrees C for 20 h. When they were studied in the charge/discharge experiments of lithium ion batteries, the initial discharge capacities reached values of 762 and 790 mAh/g, together with stable discharge capacities of 141 and 151 mAh/g after 50 cycles, respectively, which were both lower than those of nanoparticles. (C) 2012 Elsevier B.V. All rights reserved.