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Radio-frequency magnetron sputtering technique was employed to deposit transition metal doped TiO 2 thin film electrodes on polished stainless steel substrates. Rutile phase TiO 2 films have been deposited with 6% and 10% Fe, Mn and Co doping and separate coin cell type Lithium Ion Batteries (LIB's) have been prepared with these samples as anodes. LIB's with the doped thin film samples have marked very high charge storage capacities at high current rates, which are in some cases better than that obtained with pristine TiO 2 electrode. Further, among the three dopants the performance of the Fe doped samples are the best over a large no. of cycles. During the cycling test, 10% Fe doped TiO 2 electrode has marked very high specific capacity of 0.524 mAh cm−2μm−1 after 1000 cycles at low current rate of 0.13 mA cm−2 and of 0.264 mAh cm−2μm−1 after 500 cycles even at high current rate of 1.3 mA cm−2. Increase in the current rate by 10 folds has not affected the specific capacity much, manifesting excellent response of the battery at high current rate. In the present study we have applied Fe, Co and Mn doping to TiO 2 electrodes prepared under identical conditions and have compared their performances as anodes of thin film LIB's in detail and thus the results would be very useful in technological realization of these anodes in practical LIB systems. • Rutile phase TiO 2 films prepared on SS substrates by rf magnetron sputtering. • TiO 2 films have been deposited with 6% and 10% Fe, Mn and Co doping. • Coin cell type Li ion batteries have been prepared using these thin TiO 2 films as electrodes. • LIB's with doped TiO 2 films show very high charge storage capacities at high current rates. • Among the three dopants 10% Fe doped TiO 2 electrode marked highest specific capacity. [ABSTRACT FROM AUTHOR]

TiO 2 is a potential candidate for thin film electrode in Li ion batteries since it is abundant, cheap, has high theoretical specific capacity and can be produced in thin film form of desired crystallographic phase relatively easily by various physical vapor deposition techniques. Rutile phase TiO 2 thin films have been prepared by radio frequency magnetron sputtering technique on stainless steel substrates at 450 °C substrate temperature, followed by post deposition annealing in air at 600 °C. These samples have been used as anode in Li ion batteries which are subjected to discharge/charge cycles. The electrodes have been extracted by de-crimping the batteries at various stages during the 1st discharge and 1st charge cycles and structural characterizations of these samples have been carried out by Grazing Incidence X-ray diffraction measurements with a laboratory X-ray source and Extended X-ray absorption fine structure measurements using synchrotron radiation. A clear signature of rutile to anatase phase transition has been observed in the samples during 1st discharge or Li ion insertion process, which is subsequently retained during the 1st charging cycle also. This is also verified by Raman spectroscopy measurements on few samples and is further corroborated by the constant voltage plateau observed in the galvanostatic cycle (potential versus capacitance plot) of the Li ion battery also during the 1st discharge cycle. • TiO 2 films prepared on SS substrates by rf magnetron sputtering at 450 °C substrate temperature. • Films are found to preferentially acquire rutile phase by post deposition annealing in air at 600 °C. • Coin cell type Li ion batteries have been prepared using these thin TiO 2 films as electrodes. • Galvanostatic C-V measurement shows a constant voltage plateau during 1st discharge cycle. • GIXRD and EXAFS measurements show transition from rutile to anatase phase during 1st discharge cycle. [ABSTRACT FROM AUTHOR]