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Nano-crystalline TiO2 thin films have been fabricated by direct-current sputter deposition. The crystalline TiO2 films are deposited without thermal annealing. The crystal structures, morphologies and electrochemical performances of the fabricated TiO2 electrodes toward lithium have been systematically investigated. By controlling the total deposition pressures and O2 partial pressures, anatase-phase TiO2 electrodes with granular grains and spindle-like grains can be fabricated. The TiO2 electrode exhibits with granular morphology shows short discharge plateau and lower capacity. The spindle-like TiO2 electrode shows a flat plateau at ∼1.7 V, and exhibits a reversible capacity of around 330 mAhg-1 as cycled between 3.0 to 0.0 V v.s. Li/Li+ at 0.2 C. The results have demonstrated that the nano-structured spindle-like TiO2 can be used as high capacity electrodes for lithium ion thin film batteries. [ABSTRACT FROM AUTHOR]

Amorphous Si thin films have been prepared using radio-frequency magnetron sputtering. Cu nanodots of 2-10 nm in diameter were sputter deposited on the surface of Si films. The Si films modified with Cu nanodots (n-Cu/Si) were used as anodes for lithium-ion batteries. The performances of the n-Cu/Si anodes with different thickness of Si films, 120 and 1000 nm, were characterized and compared. The Cu nanodots can greatly improve the cycling stability. The amount of capacity fading was 66% after 150 cycles for the thinner Si films (120 nm), and was over 90% after 50 cycles for thicker films (1000 nm). For the n-Cu/Si films, the amount of capacity fading was 33% for thin films and 45% for thicker films. [ABSTRACT FROM AUTHOR]

Cu6Sn5 thin-film anodes have been prepared by magnetron cosputtering, and the electrochemical properties of the deposited films in relation to lithium have been investigated. Structural evolution of the Cu6Sn5 thin films was induced by in Situ substrate bias, which then resulted in different electrochemical properties. The crystallinity of the deposited thin films can be well controlled under precise substrate bias. Films deposited with substrate bias ranging from 0 to - 80 V showed nearly amorphous structure, with nanosized particles on the surface. These films exhibited typical electrochemical properties of nanocrystalline Cu6Sn5. As the substrate bias became more intense, polycrystalline Cu6Sn5 films formed. At a bias of -150 V, highly crystallized Cu6Sn5 films were obtained. The postcycled X-ray diffraction spectra indicated a Li2CuSn phase in the film made with -150 V bias. This phase was associated with the intercalation process normally found in the high-temperature-phase η-Cu6Sn5. The results show that in situ bias is able to induce phase transformation of Cu6Sn5 (η′-Cu6Sn5 ⃡ η-Cu6Sn5) without thermal annealing. The nonbias-deposited films showed electrochemical characteristics of the low-temperature η′-Cu6Sn5 phase, whereas the -150 V bias-deposited films showed properties of the high-temperature η-Cu6Sn5 phase. [ABSTRACT FROM AUTHOR]