ROMP-derived polymer binders with stepwise and facile multifunctionalization for high-performance silicon anode Li-ion batteries

Abstract

Ring-opening metathesis polymerization (ROMP) offers an efficient way to obtain high molecular weight polymers and allows the straightforward incorporation of diverse functional groups into pendant side chains. However, its application to polymer binders for silicon (Si) anode in Li-ion batteries has been rarely explored. In this work, we demonstrate that stepwise functionalization of ROMP-derived polymer binders enables systematic control over mechanical flexibility, lithium-ion affinity, and ionic conductivity, providing a promising strategy for designing next-generation binder systems for Si anodes. The carboxylic acid groups make strong binding with Si nanoparticles, and notably the ion-conductive groups introduced into the ROMP-derived binder effectively improved the initial Coulombic efficiency (ICE), reduce interfacial resistance, and stabilize the electrode interface. As a result, the fully functionalized binder achieved high reversible capacity (2495 mAh g−1) and excellent cycling stability (72.8% retention after 250 cycles). This study establishes ROMP-derived polymers as a tunable platform for binder design in high-performance Si anode by optimizing their mechanical and chemical properties through structural modification.