Alleviating Mn Ion Dissolution in LiMn2O4 by Activation of TiO2 Lewis Acid Sites in Electrospun PVA/TiO2 Quasi-Solid Polymer Electrolyte

The primary concern of interest in high-voltage cathodes such as spinel LiMn2O4 is transition metal dissolution. Though several techniques and structural modifications are continuously under examination, a crucial factor that could make a significant impact is the careful evaluation of electrolyte properties. In this regard, a PVA/TiO2 (PT) quasi-solid polymer electrolyte prepared using an electrospinning technique is employed to suppress HF scavengers, a main cause of manganese dissolution. Good electrochemical stability of 5.05 V, ionic conductivity of 0.26 × 10–5 S cm–1, stable plating–stripping, and tLi+ of 0.82 are evidence for good electrolyte performance. Lewis acid sites of TiO2 firmly hold the PF6– anions, and strong hydrogen bonding of carbonate solvents disrupts the cycle of electrolyte decomposition reactions. The capacity retention of 73% after 500 cycles at a 2C rate and post-mortem analysis of the LMO cathode provide evidence for the successful suppression of manganese dissolution using a PT electrolyte.