Synthesis and performance of cathode material LiCo0.05Mn1.95O4-aEuroparts per thousandy F y and modify by surface coating with LiCoO2

To investigate the electrochemical properties of LiCo0.05Mn1.95O4 -aEuro parts per thousand y F (y) (y = 0.025, 0.05, 0.075, 0.1, 0.15) as a cathode material for 4-V class lithium secondary batteries, spinel phases synthesized by sol-gel were examined. X-ray diffraction data reveals that all the materials synthesized are pure spinel structures. The charge-discharge curves demonstrate that LiCo0.05Mn1.95O3.9F0.1 has the best electrochemical property. LiCo0.05Mn1.95O3.9F0.1 possesses the initial and stable discharge capacity of 118.3 and 113 mAh/g after 10 cycles at 0.1 C, respectively, while LiCo0.05Mn1.95O3.9F0.1 possesses the initial and stable discharge capacity of 105.8 and 90.9 mAh/g after 40 cycles at 1 C, respectively. Both the cyclic voltammetry and electrochemical impedance explain the best electrochemical property of LiCo0.05Mn1.95O3.9F0.1 to some degree. LiCoO2-coated LiCo0.05Mn1.95O4 -aEuro parts per thousand y F (y) (7 mol%) presents an excellent reversibility than pristine one which possesses the initial and stable discharge capacity of 106.1 and 101.3 mAh/g after 40 cycles at 1 C, respectively.