Improved Electrochemical Properties of Conducting AZO-Coated Spinel LiMn2O4 at 55 °C

To improve the electrochemical properties of spinel LiMn2O4 cathode material, LiMn2O4 coated with Al doped ZnO (AZO) was prepared by sol-gel method. The effects of AZO coating on the structural and electrochemical properties were investigated by XRD, SEM, EDS, TEM, EIS, ICP-AES and charge-discharge test. The results demonstrate that AZO coating can effectively obstruct the direct contact between the cathode electrode and electrolyte and suppress the dissolution of manganese into the electrolyte. It is shown that 1.5wt% AZO-coated LiMn2O4 delivers a capacity of 114 mAh.g(-1) with a capacity retention of 95.4% after 100 cycles operated at 1C rate and 55 degrees C, which is obviously higher than that of bare LiMn2O4 (70.6%). Moreover, 1.5wt% AZO-coated LiMn2O4 presents an excellent high-rate capability with the discharge capacity of 99 mAh.g(-1) at 10C rate.