A Multilevel Buffered Binder Network for High-Performance Silicon Anodes

Developing "ideal" binders to achieve ultrahigh area-capacity stable silicon (Si) anodes remains a significant challenge. Herein, a self-healing binder with a multilevel buffered structure is designed to alleviate the structural damage and performance degradation caused by extreme volume deformation of Si. In this multilevel configuration, employing the coexistence strategy of dynamic supramolecular interactions and rigid covalent bonds, the dopamine-grafted poly(acrylic acid) (PAA-DA) possesses abundant hydrogen bonds and strong viscoelasticity, which facilitates the dynamic reconstruction of the entire network. Moreover, the hydroxyl groups on the polyethylene glycol (PVA) form a strong covalent bond network with the carboxyl groups in PAA-DA under thermal polymerization conditions to ensure the integrity of the electrode structure. At 4 A g(-1), the resulting Si electrode retains 1974.1 mAh g(-1) after 500 cycles. This binder design strategy with dynamic repair and stable network structure gives specific inspiration for developing high-energy-density batteries.