Physicochemical Properties of Li_4Ti_(4.95)Zn_(0.05)O_(12) Anode Material by a Two-Step Solid-State Method

摘要

Li_4Ti_(5-x)Zn_xO_(12) (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 Li_4Ti_5O_(12) with an ordered spinel structure indexed to the cubic Fd3m space group. The lattice parameter of the Li_4Ti_(4.95)Zn_(0.05)O_(12) sample is slightly smaller than that for the pure Li_4Ti_5O_(12) samples. SEM exhibits that the size of the Zn-doped Li_4Ti_5O_(12) and pure Li_4Ti_5O_(12) is about 1-1.5 μm. Charge-discharge tests show that Li_4Ti_(4.95)Zn_(0.05)O_(12) exhibits excellent cycling performance and higher discharge capacity than those of Li_4Ti_5O_(12) 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~+.