Physicochemical Properties of Li4Ti4.95Zn0.05O12 Anode Material by a Two-Step Solid-State Method

Abstract

Li4Ti5−x Zn x O12 (x = 0, 0.05) anode materials were prepared by a two-step solid-state method. The structure and over-discharge property of the as-prepared materials were analyzed by x-ray diffraction (XRD), scanning electron microscopy (SEM), differential capacitance, and galvanostatic charge-discharge measurements. XRD patterns demonstrate that both samples have the phase of Li4Ti5O12 with an ordered spinel structure indexed to the cubic Fd3m space group. The lattice parameter of the Li4Ti4.95Zn0.05O12 sample is slightly smaller than that for the pure Li4Ti5O12 samples. SEM exhibits that the size of the Zn-doped Li4Ti5O12 and pure Li4Ti5O12 is about 1-1.5 μm. Charge-discharge tests show that Li4Ti4.95Zn0.05O12 exhibits excellent cycling performance and higher discharge capacity than those of Li4Ti5O12 even at different charge-discharge rates. The differential capacitance curves confirm that the zinc doping is beneficial to the reversible intercalation and de-intercalation of Li+.