Enhanced electrochemical performance of high voltage spinel cathode by using fluoroethylene carbonate as an electrolyte additive

Keywords: Lithium ion battery, electrolyte additive, fluoroethylene carbonate, spinel cathode. Abstract. Spinel LiNi0.5Mn1.5O4 cathode has attracted considerable attention because of its high energy density and operating potential. However, current carbonate electrolytes cannot meet the demand of this high voltage cathode. Here, we demonstrate that fluoroethylene carbonate (FEC) substantially improve the electrochemical performance of LiNi 0.5Mn1.5O4 cathode. In presence of 2 wt % FEC, Li/LiNi0.5Mn1.5O4 cell exhibits an improved discharge capacity retention of 90.3% after 200 cycles at room temperature. When cycled at 55 °C, the cell with FEC achieves discharge capacity retention of 92.8% after 100 cycles comparing of 72.7% of the cell without FEC. Our investigation reveals that FEC alleviates the electrolyte decomposition under high voltage and temperature conditions and forms a less resistive film on the cathode surface.