Synthesis and electrochemical properties of yttrium-doped lithium titanate/graphene nanocomposites

Yttrium-doped lithium titanate/graphene oxide nanocomposites were synthesized by calcination of nanocomposite precursor, which was prepared by solvothermal method using graphene as base, tetrabutyl titanate, lithium hydroxide monohydrate and yttrium nitrate hexahydrate as raw materials, and hexadecyl trimethyl ammonium bromide as surfactant, at high temperature under the protection of N2 atmosphere. The morphology, structure and composition of the nanocomposites obtained were then characterized by SEM, XRD, EDS, Raman spectroscopy. The nanocomposites were further used in lithium-ion battery as anode material, and their electrochemical properties were evaluated by cyclic voltammetry and constant current charge-discharge cycle method. The results showed that yttrium-doped lithium titanate/graphene nanocomposites had a morphology of graphene sheets coated with flake lithium titanate. Under a current density of 100 mA/g, the nanocomposites with a yttrium dopping amount 8%(based on the amount of substance of lithium titanate, the same below) exhitbited an initial discharge capacity of 145.5 mA·h/g, and its capacity fading was 0 after 100 charge-discharge cycles, 1.59% after 200 cycles, and 3.24% after 300 cycles, which was significantly improved compared with the graphite anode whose capacity retention rate was only about 80%. The doping of yttrium and graphene coated with lithium titanate reduced the polarization degree of lithium titanate electrode in the charge and discharge cycle and improved the cycle performance of the material. © 2023 Fine Chemicals. All rights reserved.