Preparation And Electrochemical Performance Of Lithium Titanate Anode Materials For Lithium Ion Batteries

Lithium-ion batteries are increasingly used in production and life,and the demand for power density and safety of lithium-ion batteries has increased significantly in emerging electric vehicles.The anode material,the most important part of the battery anode electrode,greatly affects the performance of the battery.At present,the most widely used anode electrode material is graphite,but the graphite material may have dendrites and there are safety hazards,and there is a problem that the cycle capacity is attenuated for a long time.Spinel lithium titanate has attracted attention due to its good safety and stability.Lithium titanate has a high lithium insertion potential and a small volume change during lithium insertion.It is an excellent lithium ion battery anode material.However,lithium titanate also has problems of poor electronic conductivity and ion transport capability,which restricts its application in lithium ion batteries.In order to improve the performance of lithium titanate under large current,we prepared the LTO-AT microspheres with good performance by combining it with anatase TiO₂（AT）,and prepared the LTO-TO/rGO nanocomposites by combining with TiO₂（TO）and reduced graphene oxide（rGO）.LTO-AT microspheres composed of nanosheets were prepared by hydrothermal method.The precursors were prepared by hydrothermal method and then treated at 600°C for 4 h to obtain nano-sheet-shaped hollow microspheres.The product was tested by XRD,SEM,TEM and characterization methods to observe the effect of the presence of TiO₂ on LTO.The addition of TiO₂ does not affect the structure and morphology of the material,and creates a phase interface and lattice disorder in the material,providing a fast transmission channel for lithium ions.Electrochemical tests show that the discharge specific capacity of LTO-AT is higher than LTO at 9C at a high current of 100C,reaching 97.5mAh/g,and the capacity and capacity retention rate are better than LTO after 2000 cycles at 5C.The LTO-TO/rGO composites were prepared by hydrothermal method,and the influence of hydrothermal time on the products was explored.The graphene oxide was ultrasonically dispersed in water to obtain a GO solution,and LTO-TO was grown on GO by a hydrothermal reaction.The effects of hydrothermal reaction time on the product were investigated by means of XRD,SEM,TEM and other characterization methods and electrochemical tests.The phase composition of the product did not change after 6 h of reaction.As time went on,the LTO-TO grown on GO increased and nanosheets gradually formed,eventually forming a nanosheet array.Electrochemical tests showed that the 36h product had the best rate and cycle performance.The discharge specific capacity reached149mAh/g at 20C,and the discharge specific capacity was 138.6mAh/g after 700 cycles at5C.