A Poly Aryl Ether Sulfone Binder with Excellent Mechanical Propertiesand Adhesive Performance for High-performance Silicon Anodes in Lithium-Ion Batteries

Introduction: Silicon (Si) anodes in Lithium-Ion Batteries (LIBs) face rapid capacity decay due to severe volume expansion during cycling. This study introduces a novel Poly Aryl Ether Sulfone (PAES) binder with carboxyl groups to address this challenge. Methods: PAES was synthesized via polycondensation and evaluated as a Si anode binder. Mechanical properties (elastic modulus, hardness), adhesive strength, and electrochemical performance (cycle stability at 420/840 mA g⁻¹) were compared with conventional binders (CMC, PVDF). Results: Si@PAES demonstrated superior mechanical properties (elastic modulus: 1520.40 MPa; hardness: 23.76 MPa) and adhesion (peel force: 2.2675 N). At 1.0 mg cm⁻² Si loading, reversible capacities of 2073.8 mAh g⁻¹ (50 cycles at 420 mA g⁻¹) and 1473.8 mAh g⁻¹ (100 cycles at 840 mA g⁻¹) were achieved, indicating excellent long-term stability. Discussion: PAES’s rigid segments provide mechanical reinforcement, while polar groups (carboxyl, sulfone) enhance cohesion and interface adhesion with Si and Cu current collectors, effectively mitigating volume expansion. Conclusion: This work presents a PAES binder strategy to improve Si anode performance, offering a viable path for commercializing high-energy-density LIBs.