Nitrogen‐Doped Carbon‐Coated 2D Cobalt Phosphide Nanosheets for High‐Performance Sodium Storage

A rational structural design is an effective way to enhance the sodium storage cycle stability and reaction kinetics of metal phosphides. Therefore, nitrogen‐doped carbon‐coated CoP nanosheets are obtained by a facile solvothermal method coupled with a polydopamine coating and phosphorization strategy. Combining the advantages of the nitrogen‐doped carbon layer and the nanosheet structure, the pseudocapacitance contribution and reaction kinetics of CoP@NC are significantly enhanced compared to pure phase CoP, as evidenced by electrochemical tests including cyclic voltammetry and GITT. Based on this, CoP@NC exhibits excellent cycling stability and rate performance. A specific capacity of 169 mAh g −1 can be maintained after 100 cycles at a current density of 0.5 A g −1 , corresponding to a capacity drop of only 0.2% per cycle. In addition, the CoP@NC electrode can deliver the discharge capacities of up to 303,3 and 106.6 mAh g −1 at 0.1 and 2 A g −1 , respectively. These excellent properties demonstrate that CoP@NC is a promising anode material for sodium storage.