High electrochemical performance of Al-doped Li4Ti5O12(LTO) with prepared via sol-gel route at low pH as anode for lithium ion battery

Abstract

The synthesis and study the effect of Al-doped on the electrochemical performance of Li4Ti5O12 (LTO) have been investigated. LTO as anode material was fabricated using Lithium acetate (C3H3O2Li), Tetrabutyl titanate atau TBT (C16H36O4Ti), Hidrocloric acid (HCl) 37%, ethanol (C2H5OH) and Alumunium Acetate (CH3CO2)3 via sol-gel route. Al atom here is used to support Ti atoms in accordance with the Li4Ti(5-x)AlxO12 stoicimetry equation. There are four variations of the doping composition (x) of aluminum such as x=0, 0.01, 0.02, and 0.03. All raw materials were stoichiometrically mixed and dried at 80°C for 24 hours and crushed to become precursors of LTO and Al-doped LTO. The precursors were sintered by using high temperature furmace at 850°C for 2 hours in air atmosphere. The final product was characterized by X-ray Diffraction (XRD) to determined crystal structure and phases. The products were also characterized by Scanning Electron Microscope (SEM) to determine the sample morphology and the average particle size distribution. The electrode sheets were prepared by mixing active material powdwers with PVDF and Super P in ratio 80: 10: 10 wt%. The slurry was coated on Cu foil with doctor blade method and dried at 80 °C for 30 minutes. The electrodes were cut into circular discs with 16mm in diameter. The electrodes were arrangged with separator, metalic lithium and electrolyte become coin cell in a glove box. Automatic battery cycler was used to measure electrochemical performances and specific capacity of the cell. The XRD analysis showed that there are three main phases such as lithium titanium oxide (Li4Ti5O12/LTO), rutile phase (TiO2) and dilithium titanate (Li2TiO3). The SEM analysis showed that the surface of each sample has a different particle size which indicates that there is still agglomeration.Cyclic voltametry analysis showed that sample with Al-doped LTO 0.03 has the highest diffusion coefficient value of 7.31 x 10-10 S/cm2, while the sample without doping has the lowest diffusion coefficient of 3.27 x 10 -10 S/cm2. Charge discharge test showed that sample without doping has higher specific capacity than other samples with 181 mAh/g. The higher Al doping has the lower specific capacity of the battery.