硅/铜/碳纳米杂化材料制备及锂电性能研究

Synthesis and Electrochemical Performance of Si/Cu/C Nanohybrids

以纳米硅粉为硅源,乙酸铜为铜纳米粒子前驱体,双官能团甲基丙烯酸酯单体为溶剂和碳源,利用热引发聚合方法,结合高温氩气气氛煅烧,原位可控合成硅/铜/碳纳米杂化材料,并通过后续不同气氛(空气或者空气结合氢气)、不同温度条件下热处理,进一步调控杂化材料中碳基质含量,达到改善单质硅负极材料循环性能、提高杂化材料导电性能的目的。采用粉末衍射(XRD)、能量弥散X射线谱图(EDX)、热重分析实验(TGA)、扫描电镜(SEM)、电化学阻抗测试(EIS)以及锂离子电池循环性能测试等方法对杂化材料的结构、结晶、组成、形貌、导电性能以及锂电循环性能进行了较为系统的研究。研究结果表明,单质硅以及单质铜均匀分布在碳基质中;单质铜的形成有效提高了杂化材料的导电性;后期热处理能够进一步调控碳基质含量,从而使得杂化材料初始放电比容量从1156mAh/g提高到1997mAh/g,而循环性能得到一定程度保持。

A series of Si/Cu/C nanohybrids were synthesized using difunctional methacrylate monomer as solvent and carbon source,silicon nanoparticles as active matter,and copper acetate as precursor for copper element.Thermal polymerization was applied to form the polymer/Si/copper acetate composites,followed by high temperature calcination in argon,and annealing at moderate temperature in different atmosphere(air or air plus hydrogen).A series of different characterization methods including XRD,EDX,SEM,TGA,EIS,and cyclic performance test were applied to investigate the composition,structure,crystallinity,morphology,electron conductivity,and cyclic performance in a systematic way.The results showed that both the silicon nanoparticles and the in situ formed copper particles were homogeneously dispersed in the carbon matrix.The formation of the copper particles effectively enhanced the electron conductivity of the nanohybrid.The annealing process further adjusted the content of the carbon matrix,leading to the significant improvement of the initial specific capacity from1156mAh/g to1997mAh/g with moderate cyclic stability.