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Vol. 56 (2020), Issue 2, p. 55-63
https://doi.org/10.5281/zenodo.3747839
LiMn2O4-Norit при низкой температуре в сравнении с LiMn2O4-МУНТ и LiMn2O4-графит ЭУЗ-М в прототипе Li-аккумулятора
Abstract
УДК 541.136
Проанализированы причины падения разрядной емкости композиции LiMn2O4 шпинели с углеродным наполнителем Norit в редокс-реакции с литием при температуре 271 К с использованием циклической вольтамперометрии и импедансной спектроскопии. Проведено сопоставление электрохимического поведения композиций LiMn2O4 – Norit с поведением композиций LiMn2O4 с углеродными нанотрубками, а также композиций LiMn2O4 с природным графитом ЭУЗ-М для выявления ключевых факторов, ответственных за эффективное преобразование исследуемых композитных электродов в прототипе литиевого аккумулятора.
Ключевые слова: LiMn2O4 шпинель, наполнители Norit, многостенные углеродные нанотрубки (МУНТ), графит ЭУЗ-М, низкая температура, литиевый аккумулятор, импеданс, циклическая вольтамперометрия.
The reasons for the fall of the discharge capacity of the Norit LiMn2O4 spinel composition with a carbon filler in the redox reaction with lithium at a temperature of 271 K were analyzed using cyclic voltammetry and impedance spectroscopy. A comparison is made of the electrochemical behavior of LiMn2O4-Norit compositions, LiMn2O4-carbon nanotubes compositions, and LiMn2O4-natural EUZ-M graphite to identify the key factors responsible for the efficient transformation of the thin-film composite electrodes under study in the prototype lithium battery. Used in the work, the fillers differed in the parameters of the initial particles: nanometer Norit and multi-walled carbon nanotubes (MWCNT) and micrometer EUZ-M, as well as the surface area of the particles varying in the series Norit > MWHT > EUZ-M (1). The nature and parameters of the particles determine the parameters of the particular processes of the investigated deintercalation of electrode process. The resistance of diffusion-migration transport in the surface film of a SEI on a composite varies with the pattern as indicated in series (1). The maximum resistance to charge transfer across the interface of the SEI/composite film varies in the opposite direction as indicated in series (1). A distinctive feature of the LiMn2O4-Norit composition with a developed surface is the presence of a SEI surface film, in which 40% of the total ohmic electrode resistance can be reached. It is assumed that a decrease in the discharge capacity of the composites in the process of long cycling at a low temperature is significantly promoted by the degradation of the carbon filler.
Keywords: LiMn2O4 spinel, Norit fillers, multi-walled carbon nanotubes, graphite EUZ-M, low temperature, lithium battery, impedance, cyclic voltammetry.
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