Dual Cross-Linked Poly(ether imide)/Poly(vinyl alcohol) Network Binder with Improved Stability for Silicon Based Anodes in Lithium-Ion Batteries

Abstract

The abundance and exceptional theoretical capacity of silicon make it a leading contender for next-generation lithium-ion battery anodes. However, its practical application is significantly hindered by rapid capacity degradation arising from substantial volume fluctuations during cycling. To address this limitation, an subtly dual cross-linked binder system was developed by incorporating soft poly(vinyl alcohol) (PVA) macromolecules into a poly(ether imide) (PEI) matrix. This innovative design leverages the rigid PEI framework, fortified through chemical ester cross-linking, to effectively suppress the expansion for silicon nanoparticles. Concurrently, the reversible hydrogen bonding within PVA could dissipate the stress to inhibit the volume changes, thereby preserving the materials' mechanical stability and structural integrity. This synergistic interplay ensures a stabilized electrode interface and enhanced durability with outstanding cycling stability, that of a high specific capacity of 2126 mAh/g and 92.1% retention over 200 cycles at 0.84 A/g. Further refinement of the anode formulation enabled an impressive areal capacity of 9.3 mAh/cm² with submicron silicon, underscoring the transformative potential of this dual cross-linked system for next-generation energy storage solutions.