Understanding the mechanism of MgF 2 modification on the electrochemical performance of lithium-rich layered oxides

Abstract

In this paper, lithium rich manganese based cathode materials were successfully modified by MgF 2 and the corresponding function mechanism was studied in detail. The MgF 2 coating inhibits the activation of Li 2 MnO 3 and induces the formation of spinel phase. The MgF 2 -3 shows an enhanced initial discharge capacity of 282.6 m Ah g -1 and an improved coulombic efficiency of 87.15% compared to 267.8 m Ah g -1 and 74.41% for the pristine sample, respectively. The MgF 2 modification can effectively inhibit HF corrosion, reduce side effects and improve cycle performance. The MgF 2 -3 shows a discharge capacity of 205.6 m Ah g -1 with a retention of 80.03% and a voltage of 442.2mV after 200 cycles, while for the pristine is only 147.9 m Ah g -1 , 66.71%, 672.3 mV, respectively.