ELECTROCHEMICAL INTERCALATION OF LANTHANUM AND FULLERENE FROM NONAQUEOUS FLUORIDE SOLUTIONS – A NEW PERSPECTIVE DIRECTION IN IMPROVEMENT OF
Li_xLa_yMn_1–уO₂-ELECTRODE CAPACITY

Popova Svetlana Stepanovna, Doctor of chemical sciences, professor, sub-department of chemical technology, Engels Technological Institute (branch) of Saratov State Technical University named after Y. A. Gagarin (17 Ploshchad Svobody street, Engels, Russia), eti@techn.sstu.ru
Guseva Ekaterina Stanislavovna,Candidate of chemical sciences, doctoral candidate, 2nd category engineer, sub-department of chemical Technology, Engels Technological Institute (branch) of Saratov State Technical University named after Y. A. Gagarin (17 Ploshchad Svobody street, Engels, Russia), kett-lada@mail.ru
Frantsev Roman Konstantinovich, Candidate of chemical sciences, head of laboratory, Central Research Institute of Machine Buildung (4 Pionerskaya street, Korolyov, Russia), frantsev@bk.ru

541-138

10.21685/2307-9150-2016-3-7

Background. Despite a large volume of lithium ion accumulators production, the urge to increase their efficiency and reduce costs is still very topical. It should be noted that one of the main problems in creation of positive electrodes based on the lithiumized manganese oxide compounds with the highest characteristics is a lack of reliable, available and cheap technologies of production of materials with capability to make a reverse lithium ion intercalation that in turn will bring an increase in specific reservoir, expansion of the range of tension of cycling, and also reduction of material degradation in case of long cycling. The purpose of the work is to make a research of kinetics and a mechanism of the joint electrochemical intercalation of lanthanum and fullerene from nonaqueous fluoride containing solutions in MnO₂-electrode before it is lithiumized; and to define kinetic regularities and a mechanism of increasing capacitor characteristics, modified by fullerene and fluo-ride-ions of Li_xLa_yMn_1–yO₂.
Materials and methods. Cycling of Li_xMnO₂, Li_xLa_yMn_1–yO₂, Li_xLa_yMn_1–yO_2–σF_σ, Li_xLa_yMn_1–yO₂(C₆₀)n, Li_xLa_yMn_1–yO_2–σF_σ(C₆₀)n electrodes was carried out in the po-tentiodynamic mode. The authors calculated the specific electrode capacitance after each charge-discharge cycle. The structure of electrodes was researched by means of the X-ray phase analysis and the method of scanning electronic microscopy.
Results. The influence of simultaneous modifying of MnO2 of an electrode by lanthanum and lithium in nonaqueous organic electrolyte containing fullerene soot in addition to lithium fluoride was considered. The comparative research of separate and joint influence of the used additives was conducted, the data on characteristics of charging and digit cycles for the researched electrodes were provided. According to the obtained data the highest density of current with the identical duration of processes were observed in case of simultaneous fullerene soot and lithium fluoride additives introduction into the electrolyte solution. The greatest capacity efficiency and the lowest rate of degradation are characteristic of the samples modified by lanthanum at presence of additives of fluoride of lithium and fullerene in the solution.
Conclusions. The obtained data on the influence of additives of fullerene and fluoride-ions on kinetics of the modified MnO₂-electrode by lanthanum and on the subsequent process of intercalation-deintercalation of lithium brings us to a conclu-sion about the efficiency of using fullerene and fluorides as modifiers, promoting in-creased conservation of electrode charge and, thereby, increased cycling duration.

lithium ion accumulators, MnO2, lanthanum, lithium intercalation, fullerene, fluoride ion.

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