Highly Stretchable Conductive Glue for High-Performance Silicon Anodes in Advanced Lithium-Ion Batteries

Binder plays a key role in maintaining the mechanical integrity of electrodes in lithium-ion batteries. However, the existing binders typically exhibit poor stretchability or low conductivity at large strains, which are not suitable for high-capacity silicon (Si)-based anodes undergoing severe volume changes during cycling. Herein, a novel stretchable conductive glue (CG) polymer that possesses inherent high conductivity, excellent stretchablity, and ductility is designed for high-performance Si anodes. The CG can be stretched up to 400% in volume without conductivity loss and mechanical fracture and thus can accommodate the large volume change of Si nanoparticles to maintain the electrode integrity and stabilize solid electrolyte interface growth during cycling while retaining the high conductivity, even with a high Si mass loading of 90%. The Si-CG anode has a large reversible capacity of 1500 mA h g⁻¹ for over 700 cycles at 840 mA g⁻¹ with a large initial Coulombic efficiency of 80% and high rate capability of 737 mA h g⁻¹ at 8400 mA g⁻¹. Moreover, the Si-CG anode demonstrates the highest achieved areal capacity of 5.13 mA h cm⁻² at a high mass loading of 2 mg cm⁻². The highly stretchable CG provides a new perspective for designing next-generation high-capacity and high-power batteries.