Preparation and Electrochemical Performance of Spinel-Type Compounds Li[sub 4]Al[sub y]Ti[sub 5−y]O[sub 12] (y=0, 0.10, 0.15, 0.25)

Abstract

Ti 5Ϫy O 12 (y ϭ 0.10, 0.15, 0.25͒ were synthesized via solid-state reaction using TiO 2 -rutile, Li 2 CO 3 , and Al 2 O 3 as starting reagents. The charge-discharge cycling of the cells showed that the electrochemical performance of Li 4 Ti 5 O 12 prepared from rutile-type TiO 2 by our laboratory was as good as that produced by anatase-type TiO 2 . However, Al 3ϩ doped Li 4 Al y Ti 5Ϫy O 12 (y ϭ 0.10, 0.15) exhibited a much better electrochemical performance in comparison with undoped Li 4 Ti 5 O 12 . Among the three samples of Li 4 Al y Ti 5Ϫy O 12 (y ϭ 0, 0.10, 0.15), Li 4 Al 0.15 Ti 4.85 O 12 exhibited the largest reversible capacity and the highest coulombic efficiency. The discharge capacity values in the first and second cyclings were 195.6 and 173.6 mAh/g, respectively. The value remained 166.9 mAh/g after 30 cycles with a capacity loss of 3.86% compared to the second cycle, and the coulombic efficiency was 99.2% at the 30th cycle.Electrodes containing Li 4 Ti 5 O 12 have good Li-ion intercalation and deintercalation reversibility and exhibit no structural change ͑zero-strain insertion material͒ during charge-discharge cycling. This active material has a main discharge platform close to 1.55 V vs. Li ϩ /Li, which is very promising for use in electrodes in numerous battery applications. 1 So far, the spinel-type Li 4 Ti 5 O 12 has mainly been prepared by a solid-state reaction from TiO 2 and Li 2 CO 3 or LiOH. The reaction typically occurs within 12-24 h at 800-1000°C. [2][3][4] Titanium dioxide adopts eight different crystallographic structures. Relevant data on Li ϩ insertion exist only for anatase and rutile. Anatase is generally considered to be the most active Li ϩ insertion host; the insertion into rutile-type TiO 2 (r-TiO 2 ) is usually reported to be negligible. Thus, anatase-type TiO 2 (a-TiO 2 ) has been used in most studies as the starting material for Li 4 Ti 5 O 12 . 5 Because r-TiO 2 is a natural material, it has low cost and wide source, and a-TiO 2 changes to r-TiO 2 at high temperatures. In this paper, we use r-TiO 2 as the starting material and study its performance.Although Li 4 Ti 5 O 12 is an insulator, doping the structure with small amounts of Mg 2ϩ has been reported to improve the electronic conductivity of the spinel by many orders of magnitude. 6 Other doping ions such as Cr 3ϩ , V 3ϩ , Mn 2ϩ , Ba 2ϩ , and Sr 2ϩ have also been studied to improve the capacity and cycling property, but no satisfactory results have been obtained. 7-10 To improve the electrochemical performance of Li 4 Ti 5 O 12 , Al 3ϩ was chosen as an alternative dopant for its extreme stability in an octahedral environment and for its light weight. 11 In this paper, we report the results obtained for Li 4 Al y Ti 5Ϫy O 12 with various Al 3ϩ doping contents. The materials have been characterized by X-ray diffraction ͑XRD͒ and scanning electron microscopy ͑SEM͒ observations. The electrochemical cycling performance of Li 4 Al y Ti 5Ϫy O 12 (y ϭ 0, 0.10, 0.15, 0.25) in lithium cells was also studied. ExperimentalSample...

Preparation and re-examination of Li4Ti4.85Al0.15O12 as anode material of lithium-ion battery

“…It is interesting that the first discharge capacity of 221 mAh g À1 in this study far exceeded the reported value of 195 mAh g À1 by Huang et al [16] and the theoretical value of $175 mAh g…”

“…Such a calcination temperature to obtain a phase-pure Al-Li 4 Ti 5 O 12 was significantly lower than that via a standard solid-phase reaction. Huang et al reported a calcination temperature of 9501C for 24 h by applying rutile TiO 2 as the titanium source [16]. High calcination temperature could result in serious sintering of the oxide and also easy evaporation of lithium, which are detrimental to the high-rate performance and should be avoided.…”

Structure and physical properties of Li4Ti5O12 synthesized at deoxidization atmosphere

“…Hence, it is necessary to develop a safer alternative with excellent performance instead of graphite as the negative electrode material. Among those potential candidates, spinel Li 4 Ti 5 O 12 (LTO) is an attractive negative electrode material for lithium ion batteries because of its low cost, environmental friendliness, little irreversible capacity [1], excellent cycling performance with long cycle life [2], and especially higher lithium intercalation potential (about 1.55 V) to avoid the deposition of metallic lithium [3]. Therefore, it is widely used as an anode coupled with high potential cathode materials to replace C/LiCoO 2 cell, such as 2.0 V Li 4 [11,12].…”

Preparation and characterization of spherical La-doped Li4Ti5O12 anode material for lithium ion batteries

“…Recently, many researchers [3][4][5][6][7][8][9][10][11][12] reported their study on spinal Li 4 Ti 5 O 12 . They fixed attention on improving the conductivity and electrochemical performance in heavy current.…”