Vacancies‐Induced Delocalized States Cobalt Phosphide for Binder‐Free Anode Toward Stable and High‐Rate Sodium‐Ion Batteries

Abstract Metal phosphides with easy synthesis, controllable morphology, and high capacity are considered as potential anodes for sodium‐ion batteries (SIBs). However, the inherent shortcomings of metal phosphating materials, such as conductivity, kinetics, volume strain, etc are not satisfactory, which hinders their large‐scale application. Here, a CoP@carbon nanofibers‐composite containing rich Co─N─C heterointerface and phosphorus vacancies grown on carbon cloth (CoP 1‐x @MEC) is synthesized as SIB anode to accomplish extraordinary capacity and ultra‐long cycle life. The hybrid composite nanoreactor effectively impregnates defective CoP as active reaction center while offering Co─N─C layer to buffer the volume expansion during charge–discharge process. These vast active interfaces, favored electrolyte infiltration, and a well‐structured ion‐electron transport network synergistically improve Na + storage and electrode kinetics. By virtue of these superiorities, CoP 1‐x @MEC binder‐free anode delivers superb SIBs performance including a high areal capacity (2.47 mAh cm −2 @0.2 mA cm −2 ), high rate capability (0.443 mAh cm −2 @6 mA cm −2 ), and long cycling stability (300 cycles without decay), thus holding great promise for inexpensive binder‐free anode‐based SIBs for practical applications.