High performance of β-cyclodextrin-derived Li4Ti5O12/C anode composites for lithium-ion battery

Abstract

Li4Ti5O12/C anode material for lithium-ion batteries were successfully synthesized by two-step calcination and sol-gel method using tetrabutyl titanate, lithium acetate, citric acid, and β-cyclodextrin as starting materials. The microstructure and morphology of the materials were characterized by X-ray diffractometer, scanning electron microscope, and transmission electron microscope. The electrochemical properties of the materials were conducted by constant current charge-discharge test, AC impedance, and cyclic voltammetry. The results show that the prepared Li4Ti5O12/C composites are spinel cubic crystal with good crystallinity and without other impurities. The particle size is between 50 and 200 nm. The electrochemical properties of Li4Ti5O12 are effectively improved by carbon coating. Among these composites, Li4Ti5O12 with 5% carbon coating shows the initial discharge specific capacity of 167.1 mAh/g at 5C and a 93.3% capacity retention after100 cycles. Its reversible capacity remains 125.4 mAh/g after100 cycles at a high charge-discharge rate of 20 C.