原位生长纳米炭纤维/硅复合材料及其储锂性能

采用催化化学气相沉积法在微米硅颗粒表面原位生长纳米炭纤维得到纳米炭纤维/硅复合材料.利用SEM,TEM和XRD表征了复合材料的表面形态和微观结构,并考察了其作为锂离子电池负极材料的循环性能.电化学测试表明:与纳米纤维/硅机械混合物相比,原位生长纳米炭纤维/硅复合材料具有更高的可逆容量(1042mAh/g)和更好的循环稳定性.根据SEM和交流阻抗分析结果,分析了纳米炭纤维/硅复合材料在充放电过程中的结构演变机制,其优异的电化学性能主要来源于原位生长纳米炭纤维与硅颗粒之间良好的接触性能.

In situ growth of a carbon nanofiber/Si composite and its application in Li-ion storage

A CNF/Si composite was synthesized in situ by growing carbon nanofibers on the surface of silicon particles through catalytic chemical vapor deposition. Microstructures of the composites were characterized by scanning and trans-mission electron microscopy, and X-ray diffraction. Electrochemical measurements indicated that the composite showed higher reversible capacity (1042mAh/g) and better cyclability than did a CNF-Si mixture prepared by simple mechanical milling. A structural evolution mechanism is proposed to explain the superior electrochemical performance of the CNF/Si composite electrode in comparison with the CNF-Si mixture. Scanning electron microscopy and ac impedance analysis in-dicated that the electrochemical performance can be attributed to the good contact of the in situ grown carbon fiber with the silicon particles.