水热法制备ZnO/石墨烯复合材料及其电化学性能研究

Preparation and Electrochemical Properties of ZnO / Graphene Composites by Hydrothermal Method

采用水热法制备ZnO/石墨烯复合材料,研究了ZnO、石墨烯不同配比与其电化学性能的关系。通过X射线衍射(XRD)、扫描电镜(SEM)、恒电流充放电、循环伏安法和交流阻抗等测试方法对复合材料结构、形貌及电化学性能进行表征,并通过电池解扣结合SEM和EDS进一步研究电极充放电前后的形貌及组分变化。结果表明,Zn O与石墨烯质量比为1∶1时电化学性能最好,在50 m A/g电流密度下首次可逆比容量高达680 m Ah/g,且循环100次之后仍保持相对最高。电池解扣分析证明电极材料在充放电过程中表面会产生微裂纹影响其电化学性能。

ZnO / graphene composites were synthesized via a hydrothermal method. The crystal structure,morphology and electrochemical performance of as-synthesized ZnO / graphene composites were characterized by X-ray diffraction（ XRD）,scanning electron microscope（ SEM）,galvanostatic chargedischarge,cyclic voltammetry and electrochemical impedance spectrum. The morphology and composition changes of electrodes after charge-discharge cycles were further studied by SEM and EDS. The results indicate that the composite which of mass ratio is 1 ∶ 1 show the best electrochemical properties. At 50 m A / g,the initial reversible capacity reaches up to 680 m Ah / g and retains highest capacity after 100 cycles. Via disassembling the button cell,the formation of the micro-cracks on the electrode surface during the process of charge and discharge has been demonstrated to affect the electrochemical properties.