Influence of manganese ions dissolved from LiMn2O4 cathode on the degradation of Li4Ti5O12-based lithium-ion batteries

Abstract

A systematic investigation is conducted to evaluate the influence of dissolved manganese ions from LiMn2O4 cathode on the degradation of Li4Ti5O12-based lithium-ion batteries. Worse capacity fading is found in Li4Ti5O12-based full cells with increasing manganese ion addition. The interfacial film covered on Li4Ti5O12 anode is affected by the manganese ion contamination during cycling, which becomes thicker but more non-uniform, and is composed by less ratio of compact components and more ratio of loose components compared with that free of contamination. Such flawed passivation film cannot restrain the further penetration of electrolyte and inhibit the contact between electrolyte and Li4Ti5O12 anodes efficiently, thus triggering more interfacial reactions and that should be the reason for the more severe capacity degradation. Accordingly, we suggest that in addition to optimizing the chemistry and microstructure of Li4Ti5O12 electrode, more attention should also be paid to minimizing the destructive effect imposed on the passivation film of Li4Ti5O12 electrode by the transition metal ion contaminations.