喷雾干燥法制备线球状SiO/CNTs复合负极材料

Fabrication of Yarn-Ball Structured SiO/CNTs Anode by Spray Drying Method

以氧化亚硅(SiO)和碳纳米管(CNTs)为原料,采用喷雾干燥技术一步制备了线球状的SiO/CNTs复合负极材料,从SEM和TEM图中,可以观察到SiO微米片团聚形成二次类球型颗粒,CNTs包覆在SiO片上形成线球状结构。一方面,CNTs可以作为包覆层缓解SiO在脱嵌锂过程中的体积膨胀效应;另一方面,CNTs作为导电骨架可以有效提高复合材料的导电性,有利于电极材料容量的发挥。当CNTs的质量分数为15%时,SiO/CNTs复合负极材料发挥出最佳电化学性能,在500 mA/g的电流密度下循环300圈之后,可逆比容量为633 mA·h/g,容量保持率为62.2%。

The yarn-ball structured SiO/CNTs composites were obtained by spray drying method.As revealed in SEM and TEM images,SiO agglomerates to form secondary spherical particles,and CNTs are coated on the surface of SiO to form the yarn-ball structured material.On the one hand,CNTs can absorb the volume change stress of SiO during the cycling process.On the other hand,CNTs serve as a conductive network,it can improve the conductivity of the overall material and reduce the electrochemical impedance,which is more conducive to deliver the capacity.Among a series of samples,15% CNTs mass fraction in SiO/CNTs has the best electrochemical performance.After 300 cycles at 500 mA/g,it still delivers a reversible specific capacity of 633 mA·h/g,and the capacity retention is 62.2%.