Tin nanoparticle loaded graphite anodes for Li-ion battery applications

Nearly monosized Sn nanoparticles were produced by an in situ prepared single-source molecular precursor approach. The experimental conditions in the NaBH4 reduction of (phen)SnCl4 (phen = 1, 10 phenanthroline) in water were carefully controlled to produce two different particle size ranges, 2-5 nm (mean: 3.5 nm, standard deviation: 0.8 nm) and 7-13 nm (mean: 10.0 nm, standard deviation: 1.7 nm). The Sn nanoparticles were subsequently dispersed in graphite (KS6) and the application of the resulting nanocomposites as an active anode material for Li-ion batteries was explored. The graphite-Sn nanocomposites showed significant improvement in the cyclability of Sn over previously reported results. The cyclability improvement is believed to be due to the smallness of the Sn particles and their uniform distribution in a soft matrix (graphite) which, in addition to being a capable Li+ host, could also effectively buffer the specific volume changes in Sn-based Li storage compounds during charging (Li+ insertion) and discharging (Li+ extraction) reactions. (C) 2004 The Electrochemical Society.