Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Nano Lett. 2012 Aug 8;12(8):4124-30. doi: 10.1021/nl301657y. Epub 2012 Jul 18.
A cost-effective and scalable method is developed to prepare a core-shell structured Si/B(4)C composite with graphite coating with high efficiency, exceptional rate performance, and long-term stability. In this material, conductive B(4)C with a 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/B(4)C composite is coated with a few graphitic layers to further improve the conductivity and stability of the composite. The Si/B(4)C/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 0.3 C rate. This new structure has the potential to provide adequate storage capacity and stability for practical applications and a good opportunity for large-scale manufacturing using commercially available materials and technologies.
开发了一种经济高效且可扩展的方法，用于制备具有石墨涂层的核壳结构 Si/B(4)C 复合材料，该材料具有高效率、卓越的倍率性能和长期稳定性。在这种材料中，具有高莫氏硬度的导电 B(4)C 不仅用作球磨过程中的微/纳米磨机，以分解微米级的 Si，而且还用作导电刚性骨架，以支撑原位形成的亚 10nm Si 颗粒，从而缓解充放电过程中的体积膨胀。Si/B(4)C 复合材料涂覆有少量石墨层，以进一步提高复合材料的导电性和稳定性。Si/B(4)C/石墨 (SBG) 复合阳极在 0.3 C 倍率下经过 100 次循环后，具有约 822 mAh·g(-1)（基于整个电极的重量，包括粘结剂和导电碳）的比容量和约 94%的容量保持率，表现出优异的循环稳定性。这种新结构有可能为实际应用提供足够的存储容量和稳定性，并且为使用商业上可获得的材料和技术进行大规模制造提供了良好的机会。
