SnO_2/石墨复合材料作为锂离子电池负极材料研究

Nanosized SnO_2 / Graphite Composite as Negative Electrode Materials for Lithium Ion Batteries

自从上个世纪90年代锂离子电池应用于便携式电器以来,电池负极材料的研究就成为热点之一.在锂离子二次电池中商品化的负极材料均为碳材料,其可逆容量不高,仅为金属锂容量的十分之一左右[1].在电池首次充放电过程中不可避免地都要在碳负极与电解液的界面上反应形成覆盖在碳电极上的钝化薄层(SEI),造成不可逆能量损失,有时甚至会引起碳电极内部的结构变化和接触不良.

Nano-scale SnO2 powders were prepared by hydrolyzation. Graphite was poured into the SnCl, solution during hydrolyzation. After drying and calcining at 360 degreesC, the negative electrode composite material of nanosized SnO2 and graphite was obtained. The composite materials were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The average crystallite size was in the range of 15similar to20 nm. Electrochemical lithium insertion/extraction was studied preliminarily on the obtained composite. The discharge capacity of nanosized SnO2/graphite composite was found to have a high electrochemical reversible capacity for Li-ion insertion and extraction, which possessed the advantages of both higher discharge capacity of SnO2 and lower discharge potential of graphite. In addition, the cycle capability was also improved due to the inhibiting effect of the composite against pulverization and agglomeration to a certain extent during Li-ion insertion and extraction.