Fine powders of tin oxide doped with traces of silicon in combination with highly dispersed amorphous silicon oxide have been synthesized by an advanced ultrasonic spray method. The mixtures have been analyzed by XRD and IR. The electrochemical results showed that addition of silicon decreases the tin oxidation state, and, hence, reduces the irreversible capacity during the first discharge/charge cycle. SiO2 and Li2SiO3 appeared during the first discharging as confirmed by IR spectroscopy. Furthermore, a reversible capacity of 900 mA h/g to 950 mA h/＇g for these composites has been found, which is even higher than the theoretical value (783 mA h/g according to the Li4.4Sn). The chemical diffusion coefficients of lithium in the Li-Sn alloy phases formed (Li0.4Sn, LiSn, Li3Sn7, Li3.5Sn and Li4.4Sn) have been measured by galvanostatic intermittent titration technique (GITT). Below a Li content corresponding to Li3Sn7, a reduced voltage polarization as well as an increased lithium chemical diffusion coefficient were observed. This improved performance is due to an enhanced interfacial diffusion, caused by highly dispersed inert second phases, i.e., SiO2 and LiSi2O3.