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

Composite electrode materials Li[Li 0.13 Ni 0.2 Mn 0.47 Co 0.2 ]O 2 (LNMC)–CeO 2 –С are obtained by the coprecipitation of Co, Ni, Mn and Ce hydroxides followed by the coating of LNMC–CeO 2 composites with pyrolytic carbon. The introduction of 5% CeO 2 promotes the reduction of LNMC grain size from 190–230 to 100–170 nm and the corresponding increase in the electrochemical capacity of LNMC-CeO 2 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-CeO 2 composites. The values of the discharge capacity of LNMC-CeO 2 -C composites are superior to the capacity of LMNC-CeO 2 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÷4.6 V) promotes the increase of low rate electrochemical capacity of LNMC-CeO 2 -C composite to 220 mAh g −1 . [ABSTRACT FROM AUTHOR]