Highly Stable Solid‐Electrolyte Interphase Enabled by PGMA Anchoring Layer for Silicon‐Based Anode

ABSTRACT The cycling stability of silicon‐based anodes is severely compromised by the large volume changes of active particles during (de)lithiation, which disrupt the electrode structure due to insufficient interfacial bonding. Here, by leveraging the initiated chemical vapor deposition (iCVD) technique, we construct a poly(glycidyl methacrylate) (PGMA) anchoring interlayer on SiO x particles. This interfacial design replaces weak physical interactions with robust covalent bindings: the epoxy groups in PGMA undergo ring‐opening reactions with the poly(acrylic acid) (PAA) binder. This covalent linkage maintains direct contact between SiO x particles and the binding network during volume expansion, while enabling the conductive matrix to recover upon contraction, thereby effectively preventing particle isolation and pore formation. Consequently, the PGMA‐modified electrode exhibits significantly enhanced interfacial adhesion and structural robustness, spatially confining solid‐electrolyte interphase (SEI) growth and mitigating continuous electrolyte depletion. As a result, the proposed strategy delivers improved cycling stability, retaining 95.0% of its capacity after 300 cycles with alleviated polarization. This study offers new perspectives for designing high‐performance silicon‐based anodes by overcoming a key limitation in electrode structural stability, namely the weak interaction between silicon particles and the binder.