Ultra‐Durability and Reversible Capacity of Silicon Anodes with Crosslinked Poly‐BIAN Binder in Lithium‐Ion Secondary Batteries for Sturdy Performance

Abstract With a high theoretical gravimetric capacity of 3579 mAhg⁻¹, silicon (Si) has made a promising claim as an alternative to graphite (372 mAhg⁻¹) in lithium‐ion battery (LIB) anodes as an active material. Unfortunately, inherent failure mechanisms (pulverization, delamination, promoting thick interphase formation, and non‐conducting nature) of Si anodes have plagued their way toward commercialization. To stabilize Si anodes, this work reports the design, synthesis, and application of a conducting/crosslinked poly(BIAN) (P‐BIAN) as a polymer binder for Si anodes. Theoretical evaluation of crosslinked P‐BIAN and electrochemical characterization of anodic half‐cells show that the crosslinked P‐BIAN exhibits its versatility by a) administering mechanical robustness to stabilize Si particles, b) undergoing n‐doping owing to the low‐lying lowest unoccupied molecular orbital (LUMO) to tailor a thin solid‐electrolyte interphase (SEI), and c) maintaining electrical conductivity. This inspired Si anodes to show a high reversible capacity of ≈2500 mAhg⁻¹ for over 1000 cycles with 99.1% capacity retention at 500 mAg⁻¹ current‐rate.