Silicon (Si) anode with ultra-high capacity and low cost are highly desirable for next-generation high-energy lithium-ion batteries, whereas suffers from severe volume change that causes rapid capacity decay upon lithiation/delithiation. The development of high-performance binders to alleviate volumetric expansion and maintain integrity of Si particles remains a significant challenge. Here, reported is a novel organic/inorganic hybrid binder composed of partial neutralized polyacrylic acid (PAAS) and sodium metaborate tetrahydrate (SMTH), which achieves in-situ crosslinking upon drying wafer electrodes. The robust crosslinked network structure with borate ester bonds is successfully attained, and can be modulated by changing the content of sodium metaborate. The strong covalent bond network endows the hybrid binder system with superior mechanical properties and powerful adhesion, which improve the contact and integrity of wafer silicon electrode by suppressing volume expansion and exfoliation, therefore facilitating Li-ion migration and enhancing electrochemical performance. The resulting commercial micro-silicon wafer electrode with PAAS/0.08SMTH binder remains a reversible specific capacity of 1670 mAh g after 150 cycles at 300 mA g, largely superior to that prepared with the original PAAS binder because its reversible specific capacity was determined to be only 1046 mAh g under identical conditions. The in-situ crosslinked 3D network structure provides a facile feasible way to improve the high-capacity anode materials for lithium-ion batteries.

中文翻译：

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新型有机/无机混合粘合剂显着提高了商用微米级硅的循环稳定性

具有超高容量和低成本的硅（Si）阳极非常适合下一代高能锂离子电池，但其体积变化严重，导致锂化/脱锂时容量快速衰减。开发高性能粘合剂以减轻体积膨胀并保持硅颗粒的完整性仍然是一个重大挑战。本文报道了一种由部分中和的聚丙烯酸（PAAS）和四水偏硼酸钠（SMTH）组成的新型有机/无机混合粘合剂，它在干燥晶片电极时实现了原位交联。成功获得了具有硼酸酯键的坚固交联网络结构，并且可以通过改变偏硼酸钠的含量来调节。强大的共价键网络赋予混合粘合剂体系优异的机械性能和强大的附着力，通过抑制体积膨胀和剥落来改善硅片电极的接触和完整性，从而促进锂离子迁移并增强电化学性能。由此产生的带有 PAAS/0.08SMTH 粘合剂的商用微硅片电极在 300 mA g-1 下循环 150 次后仍保持 1670 mAh g-1 的可逆比容量，大大优于使用原始 PAAS 粘合剂制备的电极，因为其可逆比容量被确定为相同条件下仅为1046 mAh g。原位交联的3D网络结构为改进锂离子电池高容量负极材料提供了一种简便可行的方法。