In situ preparation of an advanced binder with a triple-crosslinking network for high-performance silicon anodes

Silicon serves as a promising anode material for lithium-ion batteries. However, silicon suffers from low initial coulombic efficiency (ICE) and poor cycling performance due to large volume change, lithium consumption, the formation of a solid-electrolyte interphase (SEI), and low conductivity. To improve the performance of silicon anodes, this work proposed a new strategy for the design of silicon electrode binders based on β-cyclodextrin, citric acid, and sodium alginate, where a binder with a chemical/ionic/hydrogen-bonded triple-crosslinked network was constructed in situ during electrode preparation. The binder with a triple-crosslinked network provided the silicon electrode with a high binding strength, excellent ion/electron permeation network, and robust interfacial protective layer, providing better tolerate volume changes, and inhibiting the interfacial side reactions and the formation of solid-electrolyte interphase, as well as accelerating Li+ diffusion during the charge/discharge processes. The prepared silicon electrodes had a higher ICE (92.8%), better cycling stability (1429 mAh/g after 400 cycles at 0.5 C), and superior rate performance (1274 mAh/g at 4 C). This work may guide the design of high-performance binders for silicon electrodes.