Effect of Oleic Acid Coating on Electrochemical Properties of Li4Ti5O12 Nanofiber for Anode Materials

For preparing spine! Li4Ti5O12 nanofiber, a hydrogen titanate nanofiber precursor was mixed with LiOH center dot H2O and then the mixture was treated at 130 C in an autoclave for 24 hrs. The hydrogen titanate nanofiber precursor was made using a TiO2 and NaOH solution as the starting material. As a result, the diameter of the Li4Ti5O12 nanofiber was 5-10nm and the length was over 100 nm longer fiber. The oleic acid (C17H33COOH) coated Li4Ti5O12 nanofiber with different oleic acid contents (5, 7.5, and 10 wt%) was obtained by a simple mixing method and heat treatment at 450 degrees C in a N-2 atmosphere. The results clearly revealed that the surface of the Li4Ti5O12 nanofiber was coated with an amorphous carbon layer (1 nm). The crystallinity of the samples was also enhanced. The oleic acid coated Li4Ti5O22 nanofiber (5 wt% and 7.5 wt%) displayed a much lower impedance than the Li4Ti5O22 nanofiber because of the decreased charge transfer resistance, therefore, it had an improved discharging/charging capacity, c-rate and cycle performance.