Single Atomic Cu–C3 Sites Catalyzed Interfacial Chemistry in Bi@C for Ultra–Stable and Ultrafast Sodium–Ion Batteries

Regulating interfacial chemistry at electrode–electrolyte interface by designing catalytic electrode material is crucial and challenging for optimizing battery performance. Herein, a novel single atom Cu regulated Bi@C with Cu–C3 site (Bi@SA Cu–C) have been designed via the simple pyrolysis of metal–organic framework. Experimental investigations and theoretical calculations indicate the Cu–C3 sites accelerate the dissociation of P–F and C–O bonds in NaPF6–ether–based electrolyte and catalyze the formation of inorganic–rich and powerful solid electrolyte interphase. In addition, the Cu–C3 sites with delocalized electron around Cu trigger an uneven charge distribution and induce an in–plane local electric field, which facilitates the adsorption of Na+ and reduces the Na+ migration energy barrier. Consequently, the obtained Bi@SA Cu–C achieves a state–of–the–art reversible capacity, ultrahigh rate capability, and long–term cycling durability. The as–constructed full cell delivers a high capacity of 351 mAh g−1 corresponding to an energy density of 265 Wh kg−1. This work provides a new strategy to realize high–efficient sodium ion storage for alloy–based anode through constructing single–atom modulator integrated catalysis and promotion effect into one entity.