A multifunctional supramolecular polymer binder with hard/soft phase interaction for Si-based lithium-ion batteries

Although the binder design strategy is a key factor for improving the performance of Si anodes of Li-ion batteries, single–function binders may not fulfill their diverse application requirements. In this study, a novel multifunctional polymer binder BDSA–DPA–PEGCE (BDP) incorporated by hard/soft interacting phases was designed. The hard domain of the BDP polymer binder is achieved through reversible covalent disulfide exchange, supramolecular noncovalent cooperative H-bonding, and π-π interactions, endowing self-healing ability and enhanced mechanical properties to maintain Si anodes integrity. The soft phase is dominated by the polyether segment, establishing efficient ion-hopping transportation pathways. Meanwhile, the pre-lithiation strategy is employed for compensating the consumption of Li resources. The Si-based electrodes coordinated by the BDP binder effectively limit its volume expansion, realizing improved cycling stability, high initial coulombic efficiency of 85.2%, and superior rate performance for Si-based half–cells and NCM523//Si/C full–cells. The BDP binder also promotes the formation of dense, stable and homogeneous SEI layer. This work offers valuable insights for developing multifunctional polymer binders to satisfy the specific demands of Si-based electrodes for rechargeable batteries.