硬脂酸锌热解ZnO@C复合材料的储锂性能

Lithium Storage Properties of ZnO@C Composite Derived from Pyrolysis of Zinc Stearate

ZnO作为锂离子电池负极材料存在循环稳定性和倍率性能不理想的问题。为了提升ZnO的储锂性能,科研工作者尝试对其进行改性研究,包括结构优化和材料复合改性,但通常存在制备过程较复杂的问题。本实验采用简单的高温热解法,利用硬脂酸锌为前驱体,通过在惰性气氛中高温热解,直接制备了氧化锌@三维网状碳复合材料(ZnO@C)。随后,利用扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线衍射仪(XRD)、拉曼光谱仪(Raman)、热重分析仪(TGA)等表征方法对该复合材料进行物性表征,并探讨其原位生长过程。作为锂离子电池负极材料,ZnO@C表现出较好的循环稳定性和倍率性能,当电流密度为100 mA/g时,60次循环后其仍具有369 mAh/g的可逆容量。ZnO@C较好的储锂性能主要归因于其独特的结构,穿插于ZnO颗粒中的三维网状碳不仅能增强材料的导电性,提升电极倍率性能,同时,ZnO颗粒与碳之间的空隙也可有效缓解ZnO在充放电过程中因体积膨胀/收缩而带来的电极材料粉化问题,改善电极循环稳定性。

As anode electrode material of lithium-ion battery,ZnO has the problems of poor cycle stability and rate performance.In order to improve the lithium storage performance of ZnO,researchers try to modify it,including structural optimization and composite material modification,but there are usually complex problems in the preparation process.In this experiment,zinc oxide@three-dimensional reticulated carbon composite(ZnO@C)was prepared by a simple pyrolysis method using zinc stearate as the precursor and pyrolysis in inert atmosphere.Then,the physical properties of the composite were characterized by scanning electron microscopy(SEM),transmission electron microscope(TEM),X-ray diffraction(XRD),Raman spectrometer(Raman)and thermogravimetry(TGA),and the in-situ growth process was discussed.ZnO@C,as the anode material of lithium-ion battery,has good cycle stability and rate performance.When the current density is 100 mA/g,it still has a reversible capacity of 369 mAh/g after 60 cycles.The better lithium storage performance of ZnO@C is mainly attributed to its unique structure.The three-dimensional mesh carbon interpenetrated in ZnO particles not only enhances the conductivity of the material and improves the electrode rate performance,but also effectively alleviates the electrode material pulverization caused by volume expansion/contraction during the charging and discharging process of ZnO,and improves the electrode cycle stability.