Abstract
The electric vehicle (EV) is going to be one of the most important industries in this century, and the lithium-ion batteries should be the main choice of its power. High rate charging of lithium-ion battery is the major problem of this electric device. Recently, titanium-based compounds like spinel Li4Ti5O12 has become a popular anode material for the lithium ion battery, although it has a high-rate charging property but it also has a higher voltage plateau which is too high to an anode of general lithium ion batteries, and makes the application become narrow. MCMB (meso-carbon micro beads) is extended to be the anode material of the commercial lithium ion batteries for a long period of time, which is stable in voltage, capacity and cycle life performance, but without high-rate charging capability. In this study, we combine the advantages of these two materials, using the sol-gel process to modify the MCMB by coating Li4Ti5O12 to make a new material of Li4Ti5O12/MCMB composite anode. The phase of the produced Li4Ti5O12/MCMB composites particles was determined using powder x-ray diffraction (PXRD), and the grain size and morphology of the particle were examined through the field emission scanning electron microscope (FE-SEM). Some other tests are done for checking the electrochemical properties of the Li4Ti5O12/MCMB composites anode, it do shows the high-rate charging capability, while charging at 4C, the charging capacity is 160-170 mAh/g, and while charging at 6C, it still maintains the capacity over150 mAh/g. Under the charging rate of 0.05-6C, the Li4Ti5O12/MCMB composite anode can always show a flat voltage plateau at 0.3V, after several charging and discharging cycle, it still has a high-rate charging capability, and maintains a stable capacity. Finally, we use AC impedance and cyclic voltammetry analysis to test the oxidation and reduction of this material.