Licoo < Sub > 2 < / Sub > The Positive Film And Sn - Ti Negative Film For Magnetron Sputtering Method And Performance Study

With the increasing shortage of fossil energy, it has become a top priority to develop clean, efficient and environmentally friendly energy, where energy storage systems act as a more and more important role. The lithium-ion battery has an important position in the field of new energy storage devices. Many portable electronics, such as cell phones, digital cameras and laptops, have been inseparable from the presence of lithium-ion batteries. With the development of electronic technology, the existing lithium-ion batteries can no longer meet the requirements of miniaturization of the micro-electromechanical systems. Thin film battery becomes the best choice for its suitable thickness, various shapes which make them compatible with microelectronics technology easily.In this thesis, the magnetron sputtering method was used to deposite LiCoO2cathode film and tin-titanium anode film.The LiCoO2films were deposited by radio frequency sputtering of the corresponding bulk target which was produced by cold-pressing sintering. The influence of the sputtering parameters on the films was studied symmetrically. The radio frequency power was optimized, and the as-deposited films exhibited good crystallinity at160W. It was found that the films exhibited different orientations on different substrates ranging from304stainless steel, silicon wafer, aluminum foil to gold film. The substrate temperature was set to be300-650℃, and the crystallinity got better with the increase of the substrate temperature. It was found that the LiCoO2films show better electrochemical performance with higher crystallinity. A-axis and c-axis oriented films were produced by adjusting argon oxygen ratio. The a-axis (104) oriented films exhibited ordered columnar grains laid on the substrate. It had excellent electrochemical performance. In-situ annealing can release the lattice distortion, rendering the film crystal structure distortion smaller.Sn, Ti/Sn and Sn/Ti films were fabricated by DC-sputtering. As the Sn film has a huge volume expansion and contraction in the process of discharge and charge, it leads to a poor cycle life. When Sn layer was deposited on the pre-deposited Ti layer, the resulting Ti/Sn film was not fully alloyed, which still showed the intrinsic electrochemical properties of the pure Sn. On the other hand, when we deposited Ti on the pre-deposited Sn layer, the resulting film showed different structure and electrochemical characteristics. Sn phase in the XRD patterns disappeared gradually with the increase of the Ti layer thickness, and the film was transformed into amorphous when the Ti layer was more than200nm in thickness. The similar trend was also demonstrated by SEM images. As a result, the cycle performance became better with the increase of the Ti layer thickness.