CoP/Co₂P heterostructure in N, P co-doped carbon nanofibers enable superior lithium storage via the built-in electric field

Abstract

Transition metal phosphides (TMPs) have garnered significant attention as anode for lithium-ion batteries (LIBs) owing to their high theoretical capacity and moderate Li-intercalation potential. However, TMP still suffer from challenges, including severe volume effects and poor electrical conductivity. Herein, the heterostructure nanofibers anode is synthesized by uniformly distributing CoP/Co₂P nanoparticles onto N, P co-doped carbon substrate (CoP/Co₂P/C). The built-in electric field generated by the heterostructure enhances electron/ion conductivity, provides additional Li storage sites, thereby optimizing electrochemical performance. The CoP/Co₂P/C nanofibers exhibit great cycling stability in applications as LIBs anodes, maintaining the specific capacity above 356 mA h g^-1 after 2000 cycles under 1,000 mA g^-1. By regulating the ratio of CoP to Co₂P, the numbers of heterostructure within the nanofibers were effectively controlled. Based on this, the correlation between heterostructure and electrochemical performance was analyzed. The strategy of constructing heterostructure using the same metal significantly simplified the preparation process for high-performance TMPs anode, providing a viable approach for developing novel anode for LIBs.

Keywords

Cobalt phosphide / heterostructure / built-in electric field / N / P co-doped carbon / lithium-ion batteries

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