Preparation of lithium Li4Ti5O12-graphene composite as cathode for improving lithium battery performance

Abstract

Nanocrystallization and morphological control of Li4Ti5O12 have always been the focus of many researchers. The conductivity of Li4Ti5O12 can be greatly improved by the nano-effect and the reduction of the transmission distance of Li+ ions. Spherical Li4Ti5O12 was prepared by a sol-gel method and a hydrothermal method. First, SiO2 nanoparticles were used as templates to prepare SiO2-TiO2 composites by the sol-gel method. Then, Li4Ti5O12 was synthesized by the hydrothermal method using LiOH as the lithium source. The internal SiO2 was removed by the corrosive effect of LiOH. Carbon doping and coating modification of Li4Ti5O12 have always been an important direction for the modification of Li4Ti5O12. The high conductivity of carbon materials can further improve the rate performance of Li4Ti5O12. Therefore, graphene oxide was wrapped around the prepared spherical Li4Ti5O12 surface at room temperature. Then, hollow Li4Ti5O12-graphene composites were synthesized by high-temperature calcination. The effects of different graphene contents on the D/G band ratio and cycling properties of the composites were studied.