Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
PRESTO, The Japan Science and Technology Agency (JST), 4-1-8 Honcho, Kawaguchi 332-0012, Japan.
Sci Rep. 2017 Feb 20;7:42734. doi: 10.1038/srep42734.
Nowadays, ca. 176,640 tons/year of silicon (Si) (>4N) is manufactured for Si wafers used for semiconductor industry. The production of the highly pure Si wafers inevitably includes very high-temperature steps at 1400-2000 °C, which is energy-consuming and environmentally unfriendly. Inefficiently, ca. 45-55% of such costly Si is lost simply as sawdust in the cutting process. In this work, we develop a cost-effective way to recycle Si sawdust as a high-performance anode material for lithium-ion batteries. By a beads-milling process, nanoflakes with extremely small thickness (15-17 nm) and large diameter (0.2-1 μm) are obtained. The nanoflake framework is transformed into a high-performance porous structure, named wrinkled structure, through a self-organization induced by lithiation/delithiation cycling. Under capacity restriction up to 1200 mAh g, the best sample can retain the constant capacity over 800 cycles with a reasonably high coulombic efficiency (98-99.8%).
如今，每年大约有 176640 吨（>4N）的硅（Si）用于制造半导体工业用的硅晶圆。生产高纯度硅晶圆不可避免地包括在 1400-2000°C 的高温步骤，这既耗能又不环保。效率低下，约 45-55%的昂贵硅在切割过程中仅仅作为锯末损失。在这项工作中，我们开发了一种经济有效的方法，将硅锯末回收为锂离子电池的高性能阳极材料。通过球磨工艺，获得了厚度极薄（15-17nm）、直径较大（0.2-1μm）的纳米薄片。通过锂化/脱锂循环诱导的自组织，纳米片结构转变成高性能的多孔结构，称为褶皱结构。在容量限制高达 1200mAh g 的情况下，最好的样品可以在 800 次循环以上保持恒定的容量，具有相当高的库仑效率（98-99.8%）。
