Dual dynamic network architecture toward circular utilization of bulk Si-based anodes for sustainable Li-ion batteries

초록

The rapid expansion of lithium-ion batteries to support renewable energy systems has led to a parallel increase in battery waste, highlighting the urgent need for sustainable end-of-life strategies. Silicon-based anodes, owing to their ultrahigh theoretical capacity, are considered a viable alternative to graphite but suffer from pronounced volume fluctuations. While crosslinked polymer binders are widely applied to alleviate these drawbacks, their chemical irreversibility fundamentally constrains the recyclability of the electrode. Herein, we present a reversibly crosslinkable binder based on boronic ester dynamic covalent chemistry that simultaneously enables high electrochemical performance and efficient recyclability for bulk silicon oxide anodes. The binder forms a robust supramolecular network through spontaneous interaction between boronic acid moieties and hydroxyl-functional polymers. Its dynamic bonds allow selective cleavage under mild hydrolytic conditions, enabling complete electrode components separation and material recovery. In addition, the incorporation of hindered urea endows the binder with the ability to facilitate flexible rearrangement of the network, which maintains electrode integrity even at high areal capacity (≈15 mAh cm2). This design balances mechanical integrity, ionic transport, and dynamic reconfigurability, providing a promising route toward high-performance and closed-loop recyclable silicon anode systems. © 2025 Elsevier B.V.

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