硅氧碳氮新型硅负极材料的制备及其电化学性能

Preparation and Electrochemical Properties of Novel Silicon Oxycarbonitride Anode Material

以3-氨丙基三乙氧基硅烷(APTES)与甲醛为原料通过烷氧基水解和席夫碱反应生成前驱体,高温热解制备硅氧碳氮(SiOCN)复合负极材料。比较研究了商用的电解液添加剂氟代碳酸乙烯酯(FEC)和自制的有机氟硅电解液添加剂(MFSM2)在SiOCN电池中的电化学性能。与使用基础电解液相比,在使用MFSM2和FEC后电池可逆容量从614.6 m A·h/g分别提高至899.9 m A·h/g和886.9 m A·h/g,库仑效率从58.3%分别提高至62.2%和62.8%。循环伏安、电化学阻抗谱、扫描电子显微镜等分析结果表明,加入添加剂后在SiOCN电极表面反应形成稳定均匀致密的固体电解质界面膜,减小了界面阻抗,提高了离子传输速率,从而提高了SiOCN电池的电化学性能。

A novel silicon oxycarbonitride(SiOCN)composite is synthesized through an aldimine condensation of 3-aminopropyltriethoxysilane with formaldhyde and simultaneous hydrolysis of alkoxy,followed by subsequent thermal pyrolysis.The electrochemical performance of SiOCN as anode material is comparatively studied with the addition of a commercial electrolyte additive of fluoroethylene carbonate(FEC)and a lab-made organic fluorosilane electrolyte additive(MFSM2)in the base electrolytes.In comparison to the base electrolyte,the initial reversible capacity increases from 614.6 mA·h/g to 899.9 mA·h/g and 886.9 mA·h/g for the electrolyte with MFSM2 and FEC additive,respectively.Correspondingly,the initial coulombic efficiency increases from 58.3%to 62.2%and 62.8%.The results of cyclic voltammetry,electrochemical impedance spectroscopy,and scanning electron microscopy showed that the addition of additives reacted on the surface of the SiOCN electrode to form a stable,uniform,and dense solid electrolyte interphase,which reduced the interfacial impedance and increased the ion transport rate,thus improving the electrochemical performance of the SiOCN cell.