| Lithium micro-battery has wide applications, such as smart cards, COMS-based integrated circuits and micro-devices, and as a result, has become one of the most studied branches of batteries in recent yeas. Many all-solid-state lithium micro-batteries have been reported previously. However, the properties of these batteries still need improving, especially for the improvement of the electrochemical performances of cathode films and the optimization of fabrication techniques of thin films. Accordingly, the fabrication of high-performance and low-cost cathode thin films plays an important role to develop all-solid-state lithium micro-batteries.In this thesis, the remarkable cathode LiMn2O4 was chosen as a major subjects investigated. Thin film electrode of spinel LiMn2O4 for rechargeable lithium micro-batteries was successfully prepared by a solution deposition route. The Li-Mn-0 solution was deposited on electronically conductive Au substrate by a spin coater. The effects of solvent, concentration of the solution and the rotation speed and time during spin-coating on the quality of the films were explored. At the same time, the film performance has been studied as a function of preparation condition, i.e. the initial Li/Mn molar ration, the drying temperature, the annealing temperature and time. The thermal decomposition behavior of the precursor powder was examined by TG/DSC to determine the temperature of heat-treatment. XRD, SEM and AFM were used to characterize the structures, phase composition, morphology of the thin films. The electrochemical properties of the thin films were also investigated using cyclic voltammeter (CV) and galvanostatic charge/discharge cycling. The thin films obtained from the optimal fabrication condition (Li/Mn= 1.05:2, dried at 280℃, annealed at 800℃ for 30min) were homogeneous, dense, crack-free, and showed good intercalation kinetics and very promising cycling behavior. The first discharge capacity is37.3 μAh/(cm2·μn), and the capacity loss per cycle is about 0.011 % after 50 cycles at current density of 50μA/cm2 between 3.0-4.3V.The influences of Al3+ doping on structure and electrochemical properties of LiMn2O4 thin films were also studied in this thesis. It is found that Al-doped lithium manganeseoxides keep the same structure as spinel LiMri2O4 The lattice parameters of the samples decreased with increasing amount of doping aluminum, which helps to stabilize the spinel structure. Compared with the un-doped LiMn2O4, the two-phase change of Al-doped LiAlo iMni 9O4 thin film was suppressed. The electrochemical performance tests showed the first discharge capacities decreased with the increase of doping Al, however, the cycleability was improved. According to both the capacity and the cyclic property, LiAloosMnigsC^ thin film had favorable electrochemical performance.
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