Features of electrochemical transformation of LiMn₂O₄ composition with Norit carbon filler in a model lithium accumulator

Conductive fillers play an essential role in the efficiency of the electrochemical performance of semiconducting LiMn₂O₄ spinel in a lithium accumulator. In this study, in order to improve the discharge characteristics of LiMn₂O₄ spinel in a thin-layer electrode, a Norit carbon filler with a submicron particle size was used as a filler. The composition of spinel with this filler ensures a discharge capacity of more than 100 mA h/g at a high discharge rate (more than 10 C) in the redox reaction with lithium in EC, DMC, 1 M LiClO₄ electrolytes. Decrease of capacity takes place after the 200th cycle. The causes of this decrease upon cycling and at lower temperatures were analyzed via the impedance spectroscopy method. The efficient resistance of the charge transfer through the spinel composite electrode/electrolyte interface and the diffusion of Li⁺ play key roles in the degradation processes in the intercalation/de intercalation of Li ions into/from the spinel composite. (authors)