ORIGINAL PAPER Mechanochemical synthesis and electrochemical properties of nanostructured electrode materials for Li ion batteries G. Mulas & S. Enzo & C. Bonatto Minella & E. Arca & C. Gerbaldi & N. Penazzi & S. Bodoardo & J. Hassoun & S. Panero Received: 20 November 2007 / Revised: 1 February 2008 / Accepted: 7 February 2008 / Published online: 14 March 2008 # Springer-Verlag 2008 Abstract We focus on the synthesis by ball milling and on the electrochemical characterization of nanocrystalline bimetallic and composite materials to be employed as anodes in Li ion batteries. Ni 3 Sn 4 and Ni 3 Sn 2 based compounds were obtained by ball milling of three different Ni–Sn mixtures. The properties of the resulting anodes for Li ion batteries were evaluated as a function of composi- tion. Moreover, a biphasic system is presented, with CoSn 2 and CoSn type structures, arising from the synthesis of the Sn 31 Co 28 C 41 composition. When cycled in a Li cell, this material showed a high reversible specific capacity, about 450 mA h g -1 , and a very good electrochemical and structural stability, making it of interest for application purposes. Keywords Nanostructured materials . Ball milling . Li ion batteries . Kinetics Introduction The development of advanced materials for energy storage and conversion has been receiving wide attention to meet the rising demand of clean energy technologies. In particular, a large effort is being devoted towards the improvement of the specific properties of electrochemical devices such as rechargeable lithium ion batteries, through the investigation of nanostructured bi- or multicomponent alloys for electrodes [1–6]. Besides the enhanced electro- chemical reactivity related to the thermodynamic metasta- bility, the structural features of nanocrystals could offer several advantages with respect to the fully crystalline counterparts as, for instance, short path length for electronic and cation transport, higher electrode active specific area, which can result in higher capacity and significant rate capability [1–3]. Mechanochemical synthesis by ball milling is recognised to be a powerful technique for the preparation of a variety of metastable materials including nanostructured as well as amorphous and quasicrystalline phases [7, 8]. The relative simplicity and cheapness of the technique, together with its flexibility, has stimulated recent and rising attention by the scientific community for the preparation of nanostructured materials for power sources technologies [9–12]. Along this line, in this contribution we focus on the synthesis by mechanical processing and on the electro- chemical properties of nanocrystalline tin-based alloys, which were studied as Li ion battery anode materials. An overview of more recent results of the authors is here presented, while the relevant extended discussion is reported in the cited references [13–15]. The interest in the Sn-based systems [16, 17] is related to the electro- chemical properties arising from the coupling of the specific role of Sn phase, active in the Li ion intercalation J Solid State Electrochem (2009) 13:239–243 DOI 10.1007/s10008-008-0529-z Contribution to the Fall Meeting of the European Materials Research Society, Symposium D: 9th International Symposium on Electrochemical–Chemical Reactivity of Metastable Materials, Warsaw, 17th–21st September, 2007. G. Mulas (*) : S. Enzo : C. Bonatto Minella : E. Arca Dipartimento di Chimica, Università di Sassari, Via Vienna 2, I-07100 Sassari, Italy e-mail: mulas@uniss.it C. Gerbaldi : N. Penazzi : S. Bodoardo Dipartimento di Scienza dei Materiali ed Ingegneria Chimica, C.so Duca Abruzzi 24, Politecnico di Torino, I-10129 Turin, Italy J. Hassoun : S. Panero Dipartimento di Chimica, Università di Roma “La Sapienza”, P.le Aldo Moro 5, I-00185 Rome, Italy