双层结构Si/PPy复合负极在锂离子电池中的应用

Application of Double Layer Structure Si/PPy Composite Anode in Lithium-Ion Batteries

通过微波处理聚吡咯,制备了能够储存硅颗粒的线型碳网结构,以此网络结构和微米硅颗粒作为负极片的内层、涂覆不含硅的石墨烯材料作为外层,制备了一种具有双层结构的复合负极。通过XRD、SEM、恒流充放电、循环伏安和电化学阻抗对复合负极的结构、形貌以及电化学性能进行了考察。结果表明：双层结构负极在500 m A/g的电流条件下经过100次循环,可逆比容量高达829.6 m A·h/g,容量的保持率为43.9%,与纯微米硅及单层Si/PPy负极相比,容量保持率分别同比提高了34.4%和13.1%。

A linear carbon network structure for storing silicon particles was prepared by microwave treatment of polypyrrole. This network structure and silicon particles were used as an inner layer of anode. And then, an outer layer of graphene was covered on the network structure, which formed a double layer structure composite anode. The structure, morphology and electrochemical properties of the obtained composite were characterized using X-ray diffraction, scanning electron microscopy, galvanostatic chargedischarge experiments, cyclic voltammetry and electrochemical impedance spectroscopy. The results showed that the double layer structure composite anode could deliver a specific capacity as high as 829.6 m A·h/g after 100 cycles at a current density of 500 m A/g, the capacity retention rate was 43.9 %. Compared with that of the pure micron silicon and single-layer Si/PPy anode, the capacity retention rate of double layer structure composite anode increased by 34.4% and 13.1%, respectively.