Ternary Sn–Co–C Li-ion battery electrode material prepared by high energy ball milling J. Hassoun a , G. Mulas b , S. Panero a , B. Scrosati a, * a Dipartimento di Chimica, Universita ` di Roma ‘‘La Sapienza’’, 00185 Rome, Italy b Dipartimento di Chimica, Universita ` di Sassari, 07100 Sassari, Italy Received 22 May 2007; accepted 23 May 2007 Available online 9 June 2007 Abstract The recent announcement of the launch in the market of a new type of lithium-ion battery has instilled new life in the R&D of inno- vative electrode materials and, in particular on multi-component, tin-based, nanostructured lithium metal storage anodes. Following this trend, we have synthesized by high energy ball milling a Sn–Co–C ternary compound of composition supposedly similar to that used in the new commercial battery. We have tested this material as an electrode in a single lithium cells, as well as in an original, complete lith- ium-ion battery configuration. The results demonstrate the promising feature of this compound as innovative, high-capacity lithium-ion electrode. Ó 2007 Elsevier B.V. All rights reserved. Keywords: Tin; Alloy; Composite; Ball milling; Lithium; Battery 1. Introduction Lithium metal storage materials have a very high spe- cific capacity and, due to this intrinsic value, they are con- sidered as very appealing negative electrodes to be used in replacement of conventional graphite in advanced design, lithium-ion batteries [1,2]. Accordingly, great efforts have been devoted to the development of electrode formulations capable of exploiting the full electrochemical potentiality of these materials [3]. Among them, the active/inactive nano- composite concept has been particularly investigated [4]. The concept involves the intimate mixture of two or more materials, one (e.g., Sn) electrochemically reacting with lithium, whereas the others act as an electrochemically inactive confining buffers to accommodate the large vol- ume changes which accompany the electrochemical process [1]. Particularly relevant in this respect is the work of Dahn and co-workers who, applying this concept through com- posites such as Sn–Fe–C [5] or Sn–Mn–C [6] have demon- strated that these electrodes show a considerable improvement in their cycling response in lithium cells. Recently, a Japanese Company has announced the introduction in the market of a new lithium-ion battery with the trade name of Nexelion [7–9]. The structure com- position of this battery has not yet been fully disclosed; however, it has been reported that it is based on non-con- ventional electrolyte and electrode materials, one of these being an amorphous ternary Sn–Co–C anode [9]. Although not clearly stated in the literature, one is tempted to imagine that this ternary anode exploits the concept above discussed where the main electrochemical active material is tin while the two other elements act as the supporting components. The reciprocal and combined role of cobalt and carbon, however, may be more complex than of exerting a mere buffering action. This aspect has been investigated by Dahn et al. who, by using combinato- rial and high-throughput analysis, studied Sn–Co–C thin film libraries extending over hundred different composi- tions [10]. The electrochemical characterization, based on X-ray and electrochemical studies, allowed these author to determine that carbon has a multi-fold action which 1388-2481/$ - see front matter Ó 2007 Elsevier B.V. All rights reserved. doi:10.1016/j.elecom.2007.05.033 * Corresponding author. Tel.: +39 06 4462866; fax: +39 06 491769. E-mail address: bruno.scrosati@uniroma1.it (B. Scrosati). www.elsevier.com/locate/elecom Electrochemistry Communications 9 (2007) 2075–2081