Interface Control Strategy of Synthesis LiMn2O4@Al2O3 Assisted by Tert-Butanol

LiMn 2 O 4 @Al 2 O 3 cathode materials for lithium ion batteries are prepared through an sol-gel method with the assistance of tert-butanol. A uniform amorphous Al 2 O 3 layer is formed on the surface of LiMn 2 O 4 under the control of the hydrolysis mechanism of aluminum ion (Al 3+ ) and hydroxyl group (OH). The products are investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), power X-ray diffraction (XRD), galvanostatic charge-discharge test system, electrochemical impedance spectroscopy(EIS) and inductively-coupled plasma emission spectrograph (ICP-AES). Structural and surface analysis reveal that the crystal structure and overall morphology of the LiMn 2 O 4 electrode are found to be not significant unaffected by Al 2 O 3 coating. Notably, the Al 2 O 3 -coating assistant by tert-butanol can produce a compact amorphous layer on the LiMn 2 O 4 particles, and displays capacity losses of only 92.2% after 100 cycles at 55 o C, which is much better than bare sample and the sample synthesized without the assistant of tert-butanol. Furthermore, EIS and ICP analyses show that the Al 2 O 3 coating assisted by tert-butanol significantly improves the electro-conductivity and relieves the dissolution of Mn in electrolyte.