SnO_2/中空洋葱状碳纳米复合材料的制备及电化学性能

以炭黑为原料,硝酸铁为催化剂前驱体,氮气气氛下1000℃高温炭化制备了直径为40nm的中空洋葱状碳纳米颗粒(OC).用SnCl2/乙醇溶液浸渍,空气中350℃氧化得到SnO2/OC复合材料.进一步对该复合材料进行酸处理制备OC包覆的SnO2电极材料.采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和热失重分析(TGA)对OC和SnO2/OC复合材料进行表征;利用恒电流充放电和循环伏安(CV)方法对复合材料作为锂离子电池负极材料的电化学性能进行表征.结果表明:酸处理后的复合材料的循环性能得到明显改善,50次循环后可逆容量保持为446mAh·g-1,OC起到了缓冲SnO2膨胀和阻止团聚的作用.

Preparation and Electrochemical Properties of SnO_2/Onion-Like Hollow Carbon Nanoparticle Composites as Anode Materials for Lithium-Ion Batteries

New kinds of onion-like hollowcarbon nanoparticles (OC) with amean diameter of 40 nmwere synthesized by the pyrolysis of carbon black at 1000 ℃ in a nitrogen atmosphere using ferric nitrate as the catalyst precursor. By impregnating with a SnCl2/ethanol solution and oxidation in air at 350 ℃, OC doped SnO2 nanoparticle composites were obtained. Then, by rinsing with hydrochloric acid to remove the coated SnO2 nanoparticles, OC-encapsulated SnO2 nanoparticle composites were prepared. The morphologies and structures of OC and the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The content of SnO2 in the composite was measured by thermogravimetric analysis (TGA). The electrochemical properties of the composites as anode materials for lithium-ion batteries were evaluated by galvanostatical method and cyclic voltammetry (CV). We found that after acid treatment the sample possessed a reversible capacity of 446 mAh·g-1 after 50 cycles and excellent cycle stability. This indicates that OC is a suitable matrix to buffer against volume expansion and to prevent the agglomeration of SnO2 nanoparticles.