Abstract Silicon (Si) has attracted attention for use in lithium ion batteries due to its high theoretical capacity and its natural abundance. However, significant change in the volume of Si electrodes during repeated cycles causes dramatic capacity degradation and reduces the benefits of its attractive qualities. Here, it is reported for the first time that a derivative of natural spider silk is effective for retaining the capacity and decreasing the volume expansion of Si for use in Li-ion batteries as electrodes. Relative to the Si-electrode with polyvinylidene fluoride (SPVDF), the Si-electrode containing binder with the dissolved spider silk (SWS) cells achieved significant enhanced capacities with cycling stability during repeated cycles. The SWS electrode at 250 mA g −1 showed the discharge/charge capacities of 3642/1938 mAh g−1 at 1st cycle, 1789/1541 mAh g−1 at 2nd cycle and then reduced to 1142/1054 mAh g−1 at the 5th cycle. However, the capacities of the SPVDF electrode were 3903/2694 mAh g−1, 1455/1211 mAh g−1, and 458/435 mAh g−1. Furthermore, the discharge capacity of SWS was 333 mAh g−1 at the 38th cycle, but that of SPVDF showed 323 mAh g−1 at the 7th cycle. Such superior performance with good cycling ability may be attributed to the unique properties of spider silk: the folded crystal layer with semi-amorphous structure, the superior properties of viscosity and adhesion, and the close stacking by the protein blocks as well as the side chain R-group of crystal β-sheet. The combination of these characteristics was able to restrain the deleterious change in the volume of Si materials substantially, and to provide superior electrochemical characteristics of lithium ions.

中文翻译：

---

用于锂离子电池硅基负极的蜘蛛丝粘合剂

摘要 硅（Si）因其高理论容量和天然丰度而在锂离子电池中的应用备受关注。然而，在重复循环过程中，Si 电极体积的显着变化会导致容量急剧下降并降低其吸引力的优势。在这里，首次报道了天然蜘蛛丝的衍生物可有效保持容量并减少用于锂离子电池的硅作为电极的体积膨胀。相对于含有聚偏二氟乙烯 (SPVDF) 的硅电极，含有粘合剂的硅电极与溶解的蜘蛛丝 (SWS) 电池在重复循环过程中实现了显着增强的容量和循环稳定性。SWS 电极在 250 mA g -1 下的放电/充电容量在第一次循环时为 3642/1938 mAh g-1，在第二次循环时为 1789/1541 mAh g-1，然后在第二次循环时降至 1142/1054 mAh g-1第 5 个循环。然而，SPVDF 电极的容量为 3903/2694 mAh g-1、1455/1211 mAh g-1 和 458/435 mAh g-1。此外，SWS 的放电容量在第 38 次循环时为 333 mAh g-1，而 SPVDF 的放电容量在第 7 次循环时显示为 323 mAh g-1。这种具有良好循环能力的优异性能可能归功于蜘蛛丝的独特性质：具有半非晶结构的折叠晶体层、优异的粘性和粘附性以及蛋白质块和侧链的紧密堆积晶体β-折叠的R-基团。