Peculiarities of Electrochemical Transformation of LiMn₂O₄ Spinel with Norit Carbon Filler in Lithium Accumulator Prototype

Abstract

UDC 541.136

Conductive fillers play the essential role in the efficiency of the electrochemical performance of the semiconducting LiMn₂O₄ spinel in a lithium accumulator. In this research, to improve the discharge characteristics of LiMn₂O₄ spinel in a thin-layer electrode, Norit with submicron size of the particles was used as a filler. The compositions of the spinel with that filler ensure a discharge capacity more than 100 mAh/g at a high discharge rate (more than 10 C) in the redox reaction with lithium in electrolytes of EC, DMC, 1M LiClO₄. The lowering of the capacity takes place after the 200th cycle. The causes of that lowering at cycling and at the dropping of temperature were analyzed via the impedance spectroscopy. The efficient resistance of the charge transfer through the interface spinel composite electrode/electrolyte surface and the diffusion of Li+ play the key role in degradation processes at intercalation/deintercalation of Li ions in/from the spinel composite.

Keywords: lithium-manganese spinel, lithium accumulator, discharge capacity, thin-layer electrode, carbon filler Norit.