Effect of CeO2 coprecipitation on the electrochemical performance of Li(Li,Ni,Mn,Co)O2-CeO2-C composite cathode materials

Composite electrode materials Li[Li0.13Ni0.2Mn0.47Co0.2]O-2 (LNMC)-CeO2-C are obtained by the coprecipitation of Co, Ni, Mn and Ce hydroxides followed by the coating of LNMC-CeO2 composites with pyrolytic carbon. The introduction of 5% CeO2 promotes the reduction of LNMC grain size from 190-230 to 100-170 nm and the corresponding increase in the electrochemical capacity of LNMC-CeO2 composite. The pyrolytic coating consists of the network of 2-5 nm polymer-carbon particles at the surface of LNMC crystallites. The electrochemical impedance spectroscopy data, which was performed after the galvanostatic cycling, demonstrated considerably lower charge transfer resistance of the carbon-coated composites compared to the bare LNMC and the LNMC-CeO2 composites. The values of the discharge capacity of LNMC-CeO2-C composites are superior to the capacity of LMNC-CeO2 and LMNC-C composites at all discharge rates (C/10 - 5C). The increase of the upper boundary of potentials to 4.8 V after cycling at 5C (U - 2 divided by 4.6 V) promotes the increase of low rate electrochemical capacity of LNMC-CeO2-C composite to 220 mAh g(-1). (C) 2017 Elsevier B.V. All rights reserved.