微波辅助法制备钴酸锌纳米花及其储锂性能

Microwave Assisted Preparation of Zinc Cobaltite Nanoflowers and Lithium Storage Properties

采用微波液相辅助法及退火处理制备了纳米花结构的钴酸锌(ZnCo_2O_4),并考察了不同退火温度对材料性能的影响。利用X射线衍射(XRD)仪、扫描电镜(SEM)、循环伏安(CV)法、电化学阻抗谱(EIS)和恒流充放电测试,对所制备材料的晶体结构、形貌以及电化学性能进行了分析。分析结果表明:不同退火温度均能制备出尖晶石结构的ZnCo_2O_4。随着退火温度的升高,ZnCo_2O_4纳米花趋于团聚。400℃退火制备的ZnCo_2O_4纳米花具有较好的电化学性能。在200 m A·g^(-1)的电流密度,经过50圈循环后,比容量仍高达673. 5 m A·h·g^(-1),对应的库伦效率为97. 5%,表现出了良好的循环性能和高充放电比容量。

Zinc cobaltite(ZnCo 2O 4)nanoflowers were prepared by microwave assisted liquid phase method and annealing treatment.The effects of different annealing temperatures on performance of as-prepared samples were investigated.By using X-ray Diffraction(XRD),scanning electron microscopy(SEM),cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS),and galvanostatic charge and discharge,the crystal structure,morphology and electrochemical performances of as-prepared materials were characterized and analyzed.The results show that spinel-structured ZnCo 2O 4 are prepared at different annealing temperatures.With the annealing temperatures increaseing,ZnCo 2O 4 nanoflowers tend to aggregate.ZnCo 2O 4 nanoflowers annealed at 400℃exhibit optimal electrochemical performances.And it can deliver 673.5 mA·h·g-1 after 50 cycles at current density of 200 mA·g-1,corresponding to the coulombic efficiency of 97.5%,which shows a good cycling performance and high specific charge-discharge capacity.