NANOSYSTEMS: PHYSICS, CHEMISTRY, MATHEMATICS, 2018, 9 (6), P. 775–782
Anionic redox effect on the electrochemical performance of LLNMC–CeO2–C nanocomposites
K. A. Kurilenko – Department of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
D. I. Petukhov – Department of Chemistry; Department of Materials Sciences, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia; di.petukhov@gmail.com
A.V. Garshev – Department of Chemistry; Department of Materials Sciences, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
O. A. Shlyakhtin – Department of Chemistry, M.V. Lomonosov Moscow State University, 119991 Moscow, Russia
Li[Li0.13Ni0.2Mn0.47Co0.2]O2–CeO2 composites have been obtained by coprecipitation with CeO2 and by coating with ceria followed by coating with carbon film. STEM analysis revealed the formation of 20 – 30 nm ceria particles on the surface of LLNMC grains in all cases. Both carbon-coated LLNMC-CeO2 composites and carbon-free LLNMC coated with 1 % CeO2 demonstrated enhanced capacity values that could not be explained by the charge compensation via redox of nickel and cobalt. 5 % CeO2-coprecipitated sample demonstrated the most intense anomaly in CV at U = 4.1 – 4.5 V associated with redox processes in the anionic sublattice of LLNMC and a larger charge transfer resistance compared to other composites. The maximum values of Li+ diffusion coefficient have been observed for the samples coated with 1 % CeO2. The different electrochemical behavior of these samples could be explained by the different intensity of anionic redox processes in the samples with different amount of nanocrystalline ceria.
Keywords: Li-ion batteries, cathode materials, coatings, ceria, pyrolytic carbon.
PACS 61.46+w. 61.72.Ww, 66.10.Ed
DOI 10.17586/2220-8054-2018-9-6-775-782