A stretchy binder protects the silicon A challenge in using silicon particles for lithium batteries is that the large volume changes during charge-discharge cycling cause the particles to fracture, which builds up an insulating interface layer. Choi et al. show that traditional binder materials used to cushion the silicon particles can be improved by adding small amounts of polyrotaxanes (see the Perspective by Ryu and Park). The molecules consist of multiple rings that are strung along a linear segment and stoppered at each end. Some of the rings are anchored to the polymer binder, whereas others float freely, yielding a highly mobile but connected network that anchors the binder, and thus the silicon particles, together. Science, this issue p. 279; see also p. 250 The stability of silicon microparticle anodes is enhanced by highly elastic binders incorporating polyrotaxanes. Lithium-ion batteries with ever-increasing energy densities are needed for batteries for advanced devices and all-electric vehicles. Silicon has been highlighted as a promising anode material because of its superior specific capacity. During repeated charge-discharge cycles, silicon undergoes huge volume changes. This limits cycle life via particle pulverization and an unstable electrode-electrolyte interface, especially when the particle sizes are in the micrometer range. We show that the incorporation of 5 weight % polyrotaxane to conventional polyacrylic acid binder imparts extraordinary elasticity to the polymer network originating from the ring sliding motion of polyrotaxane. This binder combination keeps even pulverized silicon particles coalesced without disintegration, enabling stable cycle life for silicon microparticle anodes at commercial-level areal capacities.

中文翻译：

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用于锂离子电池硅微粒负极的高弹性粘合剂集成聚轮烷

弹性粘合剂保护硅 将硅颗粒用于锂电池的挑战在于，充放电循环过程中的大体积变化会导致颗粒破裂，从而形成绝缘界面层。崔等人。表明可以通过添加少量聚轮烷来改善用于缓冲硅颗粒的传统粘合剂材料（参见 Ryu 和 Park 的观点）。分子由多个环组成，这些环沿线性段串成并在每端塞住。一些环固定在聚合物粘合剂上，而其他环则自由漂浮，产生高度流动但连接的网络，将粘合剂固定在一起，从而将硅颗粒固定在一起。科学，这个问题 p。279; 另见第。250 结合聚轮烷的高弹性粘合剂增强了硅微粒阳极的稳定性。先进设备和全电动汽车的电池需要能量密度不断增加的锂离子电池。硅因其优异的比容量而被认为是一种很有前途的负极材料。在重复的充放电循环中，硅会发生巨大的体积变化。这通过颗粒粉碎和不稳定的电极-电解质界面限制了循环寿命，尤其是当颗粒尺寸在微米范围内时。我们表明，将 5 重量％的聚轮烷加入到传统的聚丙烯酸粘合剂中，可以为源自聚轮烷环滑动运动的聚合物网络赋予非凡的弹性。