A new technology solution to the problem of increasing the capacity of cathodes in lithium-ion cells of the LiLaAl/LiClO₄/ LiLaMnOF(C₆₀)_n system

• E.S. Guseva, R.K. Frantsev and S.S. Popova

“Machines and apparatuses for chemical, oil-and-gas and food industries” Department, Engels technology institute named after Yu.A. Gagarin, pl. Svobody, 17, Engels, 413100 Russian Federation

Abstract: Creating new effective ways to increase the capacity characteristics of cathode materials for lithium-ion cells (LIC) and increasing their electrical conductivity and chemical resistance to electrolyte exposure by modifying their composition and structure are crucial in the electrochemical materials science. A study on the possibility of improving the electric characteristics of a MnO₂ electrode by treatment using the method of cathodic intercalation of lanthanum from an aprotic organic salt solution containing fullerene C₆₀ and fluoride ions made it possible to identify the involvement of each of the components in the formation of new Li_xLа_yMnO_2–δF_δ(C₆₀)_n phases whose structure facilitates the subsequent process of lithium intercalation–deintercalation and accumulation in the bulk of the cathode material, and to develop process recommendations in case modification is performed in potentiostatic mode: a 0.5 mol/l solution of lanthanum sulfonate La(ОНC₆H₄CОО)₃ in a mixture of propylene carbonate and dimethoxyethane PC + DME (1:1) containing C₆₀ (28.1 g/l) and LiF (14 g/l), potential Е_c = –2.9 V (relative to SSCE), duration 30 min. Subsequent intercalation–deintercalation of lithium was performed in 0.8 M solution of LiClO₄ in PC + DME (1:1) at the same potential. The inhibition of corrosion (anodic dissolution) during the charge-discharge process was hindered by the presence of lanthanum cations intercalated in the LiAl anode structure. Lanthanum cations promote an increase in inhibition of anodic processes and an increase in the number of cycles upon electrode cycling. The component composition of La_yMn_1–yO_2–δF_δ(C₆₀)_n and Li_xLa_yMn_1–yO_2–δF_δ(C₆₀)_n electrodes was determined. The regularities that we found make it possible to adjust the electrochemical activity of the cathode, increase its chemical stability, charge durability, and cycleability, and suggest it for use in lithium-ion cells (LIC). The prototype tests performed on the LIC system LiLaAl/LiClO₄/Li_xLa_yMn_1–yO_2–δF_δ(C₆₀)_n showed an increase in the capacity by 7–8% compared to the non-modified MnO₂ “cathode”.

Keywords: manganese dioxide, lithium fluoride, fullerene, lithium-ion cell, cathodic intercalation, electrochemical intercalation, modification

Int. J. Corros. Scale Inhib., 2019, 8, no. 2, 306-311 PDF (415 K)
doi: 10.17675/2305-6894-2019-8-2-12

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