水热电化学法制备LiNiO_2薄膜

Fabrication of LiNiO_2 film by hydrothermal-electrochemical method

采用水热电化学法在Ni基体上一步合成结晶完好、具有网状结构的LiNiO2薄膜。由于薄膜多孔,具有很大的内表面积,组装成电池后电解质溶液能浸入薄膜内部的毛细管中,增大电极与电解质的接触面积,使电极材料的活性得到充分发挥。循环伏安电性能测试结果表明,薄膜电极在4.3 V左右出现强氧化峰(脱锂),在3.5V左右出现还原峰(嵌锂),说明薄膜电极具有较好的电化学性能,因为LiNiO2氧化物层具有空穴导电性,是一种P型半导体。通过循环伏安法模拟水热电化学反应过程可知,在Ni基体上生成LiNiO2薄膜的反应历程为:Ni→Ni(OH)2→NiOOH→LiNiO2。

Net structure LiNiO2 film was prepared directly on Ni substrate by hydrothermal-electrochemical method. The crystal is well developed and the film is porous. The electrolyte could permeate into the capillaries of the film in the battery. The interface area between electrode and electrolyte is enlarged which enhances the activity of the electrode. The LiNiO2 films present well define anodic peaks at 4.3 V and a cathodic peak located at 3.5 V is observed, it indicate that the cyclo-ability of the LiNiO2 film is satisfying. Cyclic voltammetry was used to simulate the hydrothermal-electrochemical process and it is found that the mechanism of the LiNiO2 formation is as follows： Ni→Ni（OH）2→NiOOH→LiNiO2.