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

摘要

Nanocrystallization and morphological control of Li 4 Ti 5 O 12 have always been the focus of manyresearchers. The conductivity of Li 4 Ti 5 O 12 can be greatly improved by the nano-effect and the reductionof the transmission distance of Li + ions. Spherical Li 4 Ti 5 O 12 was prepared by a sol-gel method and ahydrothermal method. First, SiO 2 nanoparticles were used as templates to prepare SiO 2 -TiO 2 compositesby the sol-gel method. Then, Li 4 Ti 5 O 12 was synthesized by the hydrothermal method using LiOH as thelithium source. The internal SiO 2 was removed by the corrosive effect of LiOH. Carbon doping andcoating modification of Li 4 Ti 5 O 12 have always been an important direction for the modification ofLi 4 Ti 5 O 12 . The high conductivity of carbon materials can further improve the rate performance ofLi 4 Ti 5 O 12 . Therefore, graphene oxide was wrapped around the prepared spherical Li 4 Ti 5 O 12 surface atroom temperature. Then, hollow Li 4 Ti 5 O 12 -graphene composites were synthesized by high-temperaturecalcination. The effects of different graphene contents on the D/G band ratio and cycling properties ofthe composites were studied.