Transport characteristics and electrochemical properties of Y3+ doped Li4Ti5O12 as anode material

Abstract

Li4Ti5-xYxO12 (x=0, 0.05, 0.10, 0.15, 0.20) anode materials were synthesized by ball milling assisted solid-state method used Li2CO3 and anatase TiO2 as raw materials and yttrium nitrate (Y(NO3)3·6H2O) as yttrium source. The phase and morphology of the materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS), respectively. The electrochemical performance and transport characteristics of the materials were tested and analyzed by an electrochemical workstation. The results show that there is no effect of Y3+ doping on the spinel structure of LTO material. When x=0.15, the ion and electronic conductivities of the Li4Ti4.85Y0.15O12 sample are 2.68×10-7 S·cm-1 and 1.49×10-9 S·cm-1, respectively, which are an order of magnitude higher than that of the intrinsic LTO, and present good transport characteristics. Electrochemical tests show that a first discharge capacity of Li4Ti4.85Y0.15O12 sample can reach 171 mAh·g-1 at 0.1 C rate. The sample still has a higher specific capacity of 102 mAh·g-1 and 79 mAh·g-1 at a high rate of 10 C and 20 C, respectively.After 200 cycles, the capacity retention rates are 92.6% and 89.1% respectively, showing good magnification characteristics.

Keywords

• doping
• lithium titanate
• conductivity
• rare earth ion
• high rate