钠离子电池HOPG负极固体电解质界面膜的AFM研究

发布时间：2018-08-28 13:29

【摘要】：固体电解质界面膜(Solid Electrolyte Interphase,SEI)在钠离子电池(Sodium Ion Battery,NIB)中扮演着重要作用。迄今为止,对于钠离子电池SEI膜的探索仍然十分有限。本研究利用电化学原子力显微镜(Electrochemical AFM,EC-AFM),通过循环伏安法研究了钠离子电池负极材料高定向热解石墨(Highly Oriented Pyrolytic Graphite,HOPG),在碳酸乙烯酯(Ethylene Carbonate,EC)和氟代碳酸乙烯酯(Fluoroethylene Carbonate,FEC)电解液中首次充放电过程SEI膜的结构变化。通过纳米刻蚀的方法,进一步获得首次充放电结束后SEI的厚度。结合X射线光电子能谱(X-ray Photoelectron Spectroscopy,XPS)分析了HOPG在EC和FEC电解液中所形成的SEI膜的化学组成区别。研究结果表明,在EC电解液中,所生成的SEI膜在HOPG表面非台阶处较薄,但在HOPG的台阶处较厚;在FEC电解液中,所生成的SEI膜很厚,具有明显的双层结构。其中上层是由体积较大的颗粒组成,下层则由致密的小颗粒组成。
[Abstract]:Solid electrolyte interfacial membrane (Solid Electrolyte Interphase,SEI) plays an important role in sodium ion battery (Sodium Ion Battery,NIB). So far, the exploration of sodium ion battery SEI membrane is still very limited. Using electrochemical atomic force microscope (Electrochemical AFM,EC-AFM), the high directional pyrolytic graphite (Highly Oriented Pyrolytic Graphite,HOPG (Highly Oriented Pyrolytic Graphite,HOPG) of anode materials for sodium ion batteries was studied by cyclic voltammetry. The first time in the electrolyte of ethylcarbonate (Ethylene Carbonate,EC) and ethylfluorocarbonate (Fluoroethylene Carbonate,FEC) was studied. Structural changes of SEI films during charge-discharge process. The thickness of SEI after the first charge and discharge was further obtained by nano-etching. The chemical composition of SEI film formed by HOPG in EC and FEC electrolyte was analyzed by X-ray photoelectron spectroscopy (X-ray Photoelectron Spectroscopy,XPS). The results show that in the EC electrolyte, the formed SEI film is thin in the HOPG surface, but thicker in the HOPG step, and in the FEC electrolyte, the SEI film is very thick and has an obvious double-layer structure. The upper layer is composed of larger particles and the lower layer is composed of compact small particles.
【作者单位】：上海大学材料科学与工程学院;中国科学院宁波材料技术与工程研究所;
【基金】：国家重点研发计划(2016YFB0100106) 国家自然科学基金(21303236) 宁波市自然科学基金(2016A610275)~~
【分类号】：TM912

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