球磨对ZnO的结构、形貌和电化学性能的影响

Effect of Mechanical Milling on Structure, Morphology and Electrochemical Performance of Zinc Oxide Powders

通过机械球磨对ZnO粉末进行处理.采用XRD、SEM对不同球磨时间的ZnO粉末的相结构和形貌进行表征,用恒电流充放电实验研究其在锌镍电池体系中的放电特性和循环稳定性,并结合循环伏安法探讨其充放电机理.实验结果表明,球磨过程中位错的形成和运动导致晶粒尺寸的减小和晶格应变值的增大,晶粒尺寸由135.6 nm减小至17.9 nm,晶格应变值相应地从0.06%增加到0.57%.球磨处理提高了ZnO粉末的电化学反应活性,因而其放电容量逐渐增加.当球磨时间达到100 h时,ZnO的放电容量达到300.6 mAh/g,比未球磨的高50 mAh/g.

ZnO powders were treated by mechanical milling.The structure and morphology of ZnO powders milled for different periods were characterized by XRD and SEM.The discharge behavior and cycle life of ZnO electrodes in Zn/Ni batteries were studied by galvanostatic charge and discharge tests.The incorporation of cycle voltammetry was adopted to investigate charge and discharge mechanisms of ZnO electrodes.The results showed that the grain size of the powders decreased from 135.6 nm to 17.9 nm while the lattice strain increased from 0.06% to 0.57% during milling,which could be attributed to the formation and movement of dislocations.The electrochemical reaction activity of ZnO powders was improved by mechanical milling,resulting in an increase of discharge capacity.ZnO powders milled for 100 h shows a high discharge capacity of 300.6 mAh/g,which is 50 mAh/g higher than that of the unmilled ZnO powders.