Electrochemical performance of SrF2-coated LiMn2O4 cathode material for Li-ion batteries

SrF2-coated LiMn2O4 powders with excellent electrochemical performance were synthesized. The electrochemical performance of SrF2-coated LiMn2O4 electrodes was studied as function of the level of SrF2 coating. With increasing the amount of the coated-SrF2 to 2.0% (molar fraction), the discharge capacity of LiMn2O4 decreases slightly, but the cycleability of LiMn2O4 at elevated temperature is improved obviously. In view of discharge capacity and cycleability, the 2.0% (molar fraction) coated sample shows optimum cathodic behaviors. When being cycled at 55 °C, as-prepared LiMn2O4 remains only 79% of its initial capacity after 20 cycles, whereas the 2.0% (molar fraction) coated sample shows initial discharge capacity of 108 mA-h/g, and 97% initial capacity retention.