Influence of a binder on the electrochemical behaviour of Si/RGO composite as negative electrode material for Li-ion batteries

Received: 02.12.2020. Accepted: 21.12.2020. Published:30.12.2020.A composite consisting of silicon nanoparticles and reduced graphene oxide nanosheets (Si/RGO) was studied as a promising material for the negative electrode of lithium-ion batteries. Commonly used polyvinylidene fluoride (PVdF) and carboxymethyl cellulose (CMC) served as a binder. To reveal the influence of the binder on the electrochemical behaviour of the Si/RGO composite, binder-free electrodes were also prepared and examined. Anode half-cells with composites comprising CMC as a binder demonstrated the best properties: capacity over 1200 mAh·g–1, excellent cycling performance and good rate capability up to 1.0C.This work was performed with financial support from the Ministry of Science and Higher Education of Russian Federation, project ID RFMEFI60419X0235

Effect of Lithium Borate Coating on the Electrochemical Properties of LiCoO2 Electrode for Lithium-Ion Batteries

Received: 13.10.2020. Revised: 18.11.2020. Accepted: 26.11.2020. Available online: 21.12.2020.This article belongs to the regular issue.The effect of a protective coating of fused lithium borate, Li3BO3, on the physicochemical and electrochemical characteristics of LiCoO2 has been studied. A cathode material produced by the SCS method using binary organic fuel, glycine and citric acid. The influence of the experiment conditions on the morphology, crystal structure and specific surface of lithium cobaltite was studied. Electrochemical testing of LiCoO2∙nLi3BO3 samples, n = 5 and 7 mass %, has been performed in the cathode Li|Li+-electrolyte|LiCoO2∙nLi3BO3 half-cell using 1M LiPF6 in EC/DMC mixture (1:1) as electrolyte in the 2.7-4.3 V range at normalized discharge current С/10, С/5, С/2. The maximal initial discharge capacity of 185 mAh/g was detected for the samples with 5 mass % Li3BO3. The coulomb efficiency of optimal materials in the 40th cycle was 99.1%.The work was performed in accordance with the state as-signments of the Institute of Chemistry of Solids of the Ural Branch of the RAS, No. AAAA-A19-119031890026-6 and No. АААА-А19-119102990044-6, the state assignment of the Institute of Problems of Chemical Physics of the RAS, No. АААА-А19-119061890019-5, and Thematic map No. 0089-2019-0007 «Functional materials for chemical power sources»