Porous LiMn2O4 with Al2O3 coating as high-performance positive materials

In order to improve the universality of LiMn2O4 materials, LiMn2O4 coated with Al2O3 (LMO@Al) is prepared by a co-precipitated method to improve the electrochemical performance of the porous LiMn2O4 cathode. The morphologies and microstructures are characterized by X-ray diffraction, scanning electron microscope, transmission electron microscope, and energy-dispersive spectroscopy. The electrochemical performances are investigated by galvanostatic charge-discharge test system and inductively coupled plasma emission spectrograph. The results show that the Al2O3 coating uniformly as well as tightly coupled with LiMn2O4 particles. The LMO@Al cathode material also shows outstanding electrochemical behaviors. After 100 cycles, the capacitance can remain 98.6 and 91.2% at 25 and 55 °C, respectively. Moreover, the LMO@Al composite cycled reversibly at 25 °C for 10 C with stable discharge capacities of 94.4 mAh g−1. Superior electrochemical stability of the LMO@Al can be attributed to the uniform coating which inhibited the manganese dissolution and Jahn-Teller effect of LiMn2O4 materials as well as the decomposition of the electrode by HF corrosion. The LMO@Al obtained from this work can open a new possibility in high power lithium ion batteries application.