| The sol and gel were synthesized with the nickel diacetate as the nickel source, citric acid as the chelator, the distilled water, ethanol and glycol as the solvent, respectively. The nanosized NiO powder was prepared by some heat treatment techniques. The effect of solvent, anneal temperature on heat decompose of former body and the morphology, the structure and electrochemical performance of the NiO powder were investigated. Moreover, the process of deposition NiO thin film using spin coating was discussed and the influence of sintering temperature on the films morphology, structure and the electrochemical performance of NiO thin film were investigated. The reaction mechanism between NiO and Li+ was investigated by the electrochemical impedance spectroscopy. The main conclusions were as following:1. The stable sol and gel are prepared with nickel diacetate as the nickel source and citric acid as the chelator in solution at some temperature. The gel completely decomposes at 400oC and gradually forms the nanocrystalline NiO and its size becomes larger with the increasing of sintering temperature.2. The NiO powder mixed Ni is obtained at 500oC with the distilled water as the solution, and the Ni peak disappear when the sintering temperature rise to the 600°C and 700°C. And the particles reunite severity and the size of the grains is in the degree of micron. The NiO powder presents Ni phase at the sintering temperature of 500°C and 700°C with the ethanol as the solution. The NiO powder is attained at 600°C which is crystal structure integrity, particle uniformity and the size is about 50nm. At the cut-off voltage of 0-3V and the current density of 0.1mA/cm2, the NiO powder possesses the initial discharge capacity of 1200mAh/g and remains 440mAh/g after 20 cycles. The purity and uniform NiO powders are prepared at the sintering temperature of 400-700?C with glycol as solution. The nanosized NiO powder sintering at 600oC exhibits uniform particle, integrity crystal structure and 40nm spherical particle and its initial and 10th discharge special capacity of 850mAh/g and 471mAh/g, exhibits favorable electrochemical performance.3. The stable sol is synthesized using glycol as raw material, and the NiO thin film is deposited by means of dip-coating on the stainless and single crystal silicon substrate. The NiO thin film begins forming at 400oC but the crystal is worse and shows amorphous phase. With the increasing of the sintering temperature, the crystal of NiO thin film becomes perfectly and its size is larger. The NiO thin film is attained at 600 oC exhibits well amorphous, smooth surface, uniform, compact and free of cracks. At the cut-off voltage of 0-3V, the special capacity is decreasing and the cycling performance runs down with the increasing of the current density. The NiO thin film shows best the capacity and the cycling performance which the initial specific capacity is 1285mAh/g and 650mAh/g after 300cycles at the current density of 0.01mA/cm2.4. The SEI film is free at open circuit voltage during the reaction between NiO and Li+. It begins to slowly grow at polarizing voltage of 1.5V and completely forms at 0.3V in the 1st discharge. To react further with NiO, the Li+ must pass across the SEI film and produce the fine grains Ni and amorphous Li2O. The SEI film partially decomposes and the NiO and Li+ are formed by reversible reaction of Ni and Li2O during the charge course. The equivalent circuit of RS(Qdl(RCtZW))(QSEIRSEI) which can reasonably explain Li+ in the process of reaction with NiO electrode and preferable simulate the EIS measurement data and all the errors are lower than 5%.
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