MOF-derived CoP nanoparticles anchored on P, N co-doped carbon nanoframework as robust electrocatalyst for rechargeable Li-O2 batteries

Currently, transition-metal phosphides (TMPs) coupled with heteroatom-doped carbon materials have attracted promising prospects in lithium‑oxygen (Li-O2) batteries. The CoP electrocatalysts have been extensively studied as popular electrode materials because of their efficient catalytic activity. However, numerous obstacles remain in optimizing synthetic techniques and exploring electrocatalytic mechanisms for CoP-based electrocatalysts. Herein, metal-organic frameworks (MOFs)-derived CoP nanoparticles anchored on P, N co-doped carbon nanoframeworks (CoP@PNCFs) are successfully designed at different phosphorization temperatures. The effects of the concentration of CoP active species, and the amount of P and N doping on the electrochemical performances are comparatively investigated and compared for different catalysts. The optimal catalyst, CoP@PNCF-700, displays high CoP active component, pyridinic-N and graphitic-N content, and abundant defect structures to enhance the electrochemical activity. More importantly, the CoP@PNCF-700 catalytic Li-O2 batteries deliver a high discharge specific capacity of 9630.5 mAh g−1 at 100 mA g−1 and a prominent long cycling stability of 187 cycles with a fixed capacity of 500 mAh g−1 at 200 mA g−1. This effort provides a facile strategy for designing cost-effective electrocatalysts for other energy-storage systems.