Deprotonation-driven dynamic self-assembly enables an ion-conductive self-adapting binder for lithium-ion batteries

Abstract

Since traditional polymeric binders fail to alleviate the drastic volumetric changes of silica-based materials upon repeated charge/discharge cycles, dependable yet efficient binders are needed urgently to achieve high energy density LIBs. Here, an ion-conductive self-adapting binder with enhanced interfacial adhesion, fast ionic transport and dynamic structural adjust-ability is fabricated via the deprotonation-driven dynamic self-assembly. The deprotonation process results in the more stretched chains of polyacrylic acid (PAA) in PEA(polyetheramine)/PAA, and meanwhile, the robust 3D dynamic cross-linked network is established by the electrostatic bonding of -NH₃⁺ and -COO⁻, as well as the hydrogen bonding of the donors and receptors. The proposed deprotonation reagent (PEA) possesses rotatable ether chains, which can not only form the flexible skeletons, but also ensure effective interaction of ether groups with Li⁺ to establish rapid ion transportation path. Accordingly, this new binder achieves a high adhesive shear strength while maintaining a relatively high Li⁺ conductivity, and therefore give it good adaptability to silica-based anodes. Furthermore, the assembled NCM811/Si/C full coin cells and full pouch cells also display high capacity and long-term stability. This work enlightens the structural design of advanced aqueous binders and paves the way for fabricating high-energy-density batteries and beyond.