Kinetics and mechanism of distribution of lanthanum ions in MnO2 structure in the presence of fluoride ions

• E.S. Guseva

Yu.A. Gagarin Saratov State Technical University, Engels Institute of Technology (branch), ul. Politekhicheskaya, 77, 410054 Saratov, Russian Federation

Abstract: The study focused on improving the electrical characteristics of a MnO₂ electrode by cathodic incorporation of lanthanum from an aprotic organic solution of a salt containing fluoride ions made it possible to identify the extent of participation of each component in the formation of new
Li_хLа_уMnO_2-δF_δ phases with a structure that facilitated the process of subsequent intercalation–deintercalation of lithium and its accumulation in the cathode material, and to develop technology recommendations for the modification process conducted in potentiostatic mode: 0.5 mol/L lanthanum sulfanilate solution in a mixture of propylene carbonate with dimethoxyethane, PC+DME (1:1), which contained LiF (14 g/L); the potential was E_c=2.9 V (relative to SCE); the time was 30 min. Subsequent lithium intercalation-deintercalation was carried out in 0.8 M solution of LiClO₄ in the PC+DME (1:1) mixture at the same potential. The presence of lanthanum cations that were incorporated into the structure of the LiAl anode prevented the inhibition of anodic dissolution (corrosion) during the charge-discharge process. Lanthanum cations contributed to the elevated inhibition of anodic processes and increased the number of cycles resulting from the electrode cycling [1, 2].

Keywords: fluoride ions, lanthanum, electrochemical modification, intercalation, lithiation, manganese dioxide, lithium, anode corrosion resistance

Int. J. Corros. Scale Inhib., 2020, 9, no. 1, 219-227 PDF (767 K)
doi: 10.17675/2305-6894-2020-9-1-13

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