A cost effective and scalable method is developed to prepare a core-shell structured Si/B4C composite with graphite coating with high efficiency, exceptional rate performance and long-term stability. In this material, conductive B4C with high Mohs hardness serves not only as micro-/nano- millers in the ball-milling process to break down micron-sized Si but also as the conductive rigid skeleton to support the in-situ formed sub-10 nm Si particles to alleviate the volume expansion during charge/discharge. The Si/B4C composite is coated with a few graphitic layers to further improve the conductivity and stability of the composite. The Si/B4C/graphite (SBG) composite anode shows excellent cyclability with a specific capacity of ~822 mAh?g-1 (based on the weight of the entire electrode, including binder and conductive carbon) and ~94% capacity retention over 100 cycles at 0.8C rate. This new structure has the potential to provide adequate storage capacity and stability for practical applications, and good opportunity for large scale manufacturing using commercially available materials and technologies.
Revised: October 11, 2012 |
Published: August 8, 2012
Citation
Chen X., X. Li, F. Ding, W. Xu, J. Xiao, Y. Cao, and P. Meduri, et al. 2012.Conductive Rigid Skeleton Supported Silicon as High-Performance Li-Ion Battery Anodes.Nano Letters 12, no. 8:4124–4130.PNNL-SA-87678.doi:10.1021/nl301657y