Journal of Power Sources 136 (2004) 72–79 Structural studies of Li 4/3 Me 5/3 O 4 (Me = Ti, Mn) electrode materials: local structure and electrochemical aspects C.M. Julien a , M. Massot b , K. Zaghib c,∗ a Laboratoire des Milieux Désordonnés et Hétérogènes, CNRS-UMR 7603, Université Pierre et Marie Curie, 140 rue de Lourmel, 75015 Paris, France b Laboratoire de Physique de la Matière Condensée, CNRS-UMR 7602, Université Pierre et Marie Curie, 4 Place Jussieu, Case 77, 75252 Paris cedex 05, France c Institut de Recherche d’Hydro-Québec (IREQ), 1800 Boul, Lionel-Boulet, Varennes, Que., Canada J3X 1S1 Received 5 April 2004; accepted 1 May 2004 Available online 28 July 2004 Abstract Raman scattering spectroscopy have been applied to the study of local structure of Li 4/3 Me 5/3 O 4 (Me = Ti, Mn) spinel oxides used as electrode materials for rechargeable lithium batteries and hybrid supercapacitors. We report the analysis of their vibrational spectra using both the classical factor group analysis and a local environment model. Electrochemical performance was carried out using a lithium cell with solvent-free solid-polymer. Raman spectra of Li 4/3+x Me 5/3 O 4 spinels are compared and analyzed on the basis of structural modifications of their lattices upon lithium insertion. © 2004 Elsevier B.V. All rights reserved. Keywords: Spinel; Lattice dynamics; Raman spectroscopy; Lithium batteries 1. Introduction Recently, lithium titanium oxide spinels are becoming the promising negative electrode materials in terms of the in- tercalation potential, cyclability and rate capability for the development of polymer (or ceramic) lithium-ion batteries and hybrid supercapacitors [1–4]. The [Me 2 ]O 4 framework of an Li[Me 2 ]O 4 spinel is an attractive host structure for lithium insertion–extraction reactions because it provides a three-dimensional network of face-sharing tetrahedra and octahedra for lithium ion diffusion. The zero-strain insertion material Li 4/3 Ti 5/3 O 4 (Li 4 Ti 5 O 12 ) was intensively studied because it exhibits the best behavior and reversibly inserts 0.7–1.0 Li per mole of oxide at 1.55 V leading to a spe- cific capacity of 150 mAh/g (against a theoretical capacity of 175 mAh/g) [3–10]. The exceptional stability of this elec- trode to electrochemical cycling has been demonstrated by Rossen et al. [6] and can be attributed to the stability of the [Ti 1.67 Li 0.33 ]O 4 framework and to the minimal dilation (<1%) of the cubic unit cell that occurs on lithium inser- ∗ Corresponding author. Tel.: +1 450 652 8019; fax: +1 450 652 8424. E-mail address: zaghib.karim@ireq.ca (K. Zaghib). tion. The demonstration of the use of Li 4 Ti 5 O 12 as a neg- ative electrode in a high-power lithium battery with safety concern has been done. Excellent cycle life was achieved for Li 4 Ti 5 O 12 //LiCoO 2 cells, as is expected with lithium intercalation–deintercalation into stable metal oxide struc- tures [11]. Lithium titanate Li 1+z Ti 2−z O 4 are rather complex materi- als and show a homogeneity range for 0 ≤ z ≤ 0.33 that en- ables it to exhibit a varied fundamental properties. LiTi 2 O 4 is a dark-blue metallic compound whereas the end-member Li 4/3 Ti 5/3 O 4 is white and insulating. According to previ- ous studies [5–8], the spinel phase LiTi 2 O 4 consists of a close-packed array, in which oxygen atoms occupy 32e sites of space group Fd3m, octahedral 16d sites and tetrahedral 8a sites are fully occupied by metal ions (here titanium) and lithium. In the case of Li 4/3 Ti 5/3 O 4 which has a higher Li/Ti ratio (0.8) than LiTi 2 O 4 (0.5), substitution of titanium by lithium ions occurs in octahedral sites. Ohzuku et al. [8] have suggested the following formula Li 8a [Li 1/3 Ti 5/3 ] 16d O 4 . According to Bach et al. [10] the structure of Li 4+x Ti 5 O 12 is practically unchanged as Li accommodation proceeds since the typical diffraction pattern of the parent oxide is recovered, even at a high depth of discharge. For instance, at x = 0.9, the spinel structure is maintained with only a 0378-7753/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.jpowsour.2004.05.001