钙钛矿型LaCoO3电化学储锂的形貌调制效应

采用不同方法制备了块状(Bulk)、 纳米球状(NPs)及三维有序多孔(3DPF)钙钛矿型LaCoO₃电极材料, 并考察了材料的形貌、 结构与电化学储锂之间的相关性. 结果表明, 不同形貌的电极材料均呈钙钛矿型晶体结构, 但电化学储锂性能却表现出巨大差异: 在500 mA/g的电流密度下, 块状、 纳米球状及三维有序多孔LaCoO₃电极经350次循环后放电比容量分别为157, 579和648 mA·h/g. 电化学性能的迥异主要归因于所制备的纳米及多孔结构使活性材料与电解液之间的接触面积增大, 反应活性位点明显增多, 传质电阻降低, 从而使电子传输和Li离子的嵌入/脱嵌过程得到显著改善.

Effect of Morphological Tuning on Electrochemical Performance of Perovskite LaCoO3 Anodes†

The perovskite-type LaCoO₃ electrode materials with the morphology of bulk, spherical nanoparticles(NPs) and three-dimensional porous framework(3DPF) were prepared to investigate the relations between the morphology and electrochemical lithium storage properties. It is demonstrated that the electrode materials with different morphologies all show the same perovskite structure, but there is a huge difference in specific capacities. At a current density of 500 mA/g, the specific capacities of the bulk, nano-particles, and three-dimensionally porous framework LaCoO₃ electrodes finally stabilized at 157, 579 and 648 mA·h/g, respectively. The improved specific capacity and cycling stability of porous framework LaCoO₃ are mainly attributed to the larger contact area between the active material and the electrolyte, the smaller particles, the more active sites, and the lower transfer resistance and better retention.