Electrode Properties in Mixed Imidazolium Ionic Liquid Electrolyte

Abstract

The compatibility of the mixed electrolyte of two ionic liquids based on 1,3-substituted imidazolium cations with lithium manganese oxide LiMn₂O₄, lithium iron phouphate LiFePO₄, graphite, and a hard carbon has been confirmed. For LiMn₂O₄ and LiFePO₄, the mixed imidazolium ionic liquid electrolyte provides slightly higher plateau in discharge curves, while the initial capacity is slightly lower, when compared with piperidinium ionic liquid. In case of LiMn₂O₄, the capacity in the mixed ionic liquid is recovered by subsequent cycling. The thermal stabilities of charged positive electrodes with the mixed ionic liquid, as well as with the piperidinium one, from accelerating rate calorimetry are far over those in conventional carbonate electrolyte. A hard carbon electrode is compatible with the mixed ionic liquid electrolyte.