Interfacially Reinforced Crosslinked Binder with Structural Integrity for Stable Micro-Sized Silicon Anodes in All-solid-state Batteries

초록

All-solid-state batteries (ASSBs) have attracted considerable attention as next-generation energy storage systems owing to their high energy density and safety. However, their performance is critically limited by insufficient solid-solid interfacial contact and severe chemomechanical degradation, particularly for micro-sized silicon (& micro;Si) anodes that undergo large volume changes during cycling. In this study, we report an interfacially reinforced crosslinked binder (IRCB) designed to stabilize & micro;Si anodes in ASSBs by simultaneously addressing mechanical integrity and interfacial stability. The IRCB is synthesized via a facile crosslinking reaction between 1,4-butanediol diglycidyl ether and ethylenediamine, forming a robust 3D polymer network. This crosslinked structure enhances mechanical constraint, maintains interparticle contact, and provides ether-rich domains that facilitate Li+ transport, while strong hydrogen bonding improves adhesion to & micro;Si surfaces. As a result, carbon-free & micro;Si anodes employing IRCB exhibit markedly improved electrochemical stability, delivering 90% capacity retention after 300 cycles at 1 C, compared with only 16% for conventional PVDF-based electrodes. Structural and interfacial analyses reveal that IRCB effectively mitigates particle displacement and suppresses interfacial degradation with sulfide solid electrolytes. This work demonstrates that rational binder engineering is a key enabler for achieving stable and high-performance & micro;Si anodes in ASSBs.

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