Electrically and Ionically Conductive Network with High Stretchability Enables High‐Performance Micro‐Sized Silicon Anode

Silicon is recognized as a promising anode material for energy‐dense lithium‐ion batteries due to its high theoretical specific capacity, but encounters great challenges, including huge volume change and unstable interfaces during the cycling process. An electrically and ionically conductive network with high stretchability is reported, prepared from single‐walled carbon nanotubes and a polymeric network (PAA‐EP), which enables a high‐performance micro‐sized silicon (μSi) anode. The PAA‐EP network is synthesized through the cross‐linking reaction between poly(acrylic acid) and terminal hydroxyl polyethers. Such a binder design combines high strength with exceptional toughness by integrating the stiffness of poly(acrylic acid) with the pliability of polyethers. The as‐prepared μSi anode with PAA‐EP exhibits extremely high initial specific capacity (4030.4 mAh g −1 ), unprecedented long‐term cycle stability (capacity remaining 904 mAh g −1 after 500 cycles at 2.0 A g −1 ), and superior rate performance (1692 mAh g −1 at 3.0 A g −1 ). Meanwhile, this network also enables SiO x anodes with an ultrahigh capacity retention of 98.52% at 0.75 A g −1 after 500 cycles (calculated from the 26th cycle), highlighting promising commercial application prospects. This work provides a straightforward yet efficient strategy for stabilizing Si‐based anodes, which paves a new way to improve the electrochemical performance of various high‐capacity electrode materials.