An Endotenon Sheath-Inspired Double-Network Binder Enables Superior Cycling Performance of Silicon Electrodes.

Silicon (Si) has been regarded as an alternative anode material to traditional graphite owing to its higher theoretical capacity (4200 vs. 372 mAh g). However, Si anodes suffer from the inherent volume expansion and unstable solid electrolyte interphase, thus experiencing fast capacity decay, which hinders their commercial application. To address this, herein, an endotenon sheath-inspired water-soluble double-network binder (DNB) is presented for resolving the bottleneck of Si anodes. The as-developed binder shows excellent adhesion, high mechanical properties, and a considerable self-healing capability mainly benefited by its supramolecular hybrid network. Apart from these advantages, this binder also induces a LiN/LiF-rich solid electrolyte interface layer, contributing to a superior cycle stability of Si electrodes. As expected, the DNB can achieve mechanically more stable Si electrodes than traditional polyacrylic acid and pectin binders. As a result, DNB delivers superior electrochemical performance of Si/Li half cells and LiNiCoMnO/Si full cells, even with a high loading of Si electrode, to traditional polyacrylic acid and pectin binders. The bioinspired binder design provides a promising route to achieve long-life Si anode-assembled lithium batteries.