Metal-organic framework-derived bimetallic phosphide NiCoP hollow structured in P, N co-doped porous carbon networks as high-performance bifunctional electrocatalyst for enhanced rechargeable Li - O 2 batteries

Owing to the high energy density and safe energy storage, lithium-oxygen batteries (LOBs) have earned much attention and become a strong contender among the next-generation battery system. However, sluggish reaction kinetics during discharge and charge reactions and inferior structural stability seriously impede their further development. We have proposed a dopamine-coated strategy to synthesize the hollow nanostructured Ni - Co mixed bimetallic phosphide (NiCoP@PNCF) cathode catalyst. Benefiting from the synergistic effects of heteroatom-doped carbon shell and NiCoP nanoparticles, hollow-structured NiCoP@PNCF cathode could expose the abundant active sites to accelerate the ion transport efficiency and improve the bifunctional reaction kinetics. Meanwhile, density functional theory calculation reveals the mechanism of the improved conductivity and electrochemical activity. Taking advantage of the structural and compositional merits, the LOBs equipped with NiCoP@PNCF catalyst possess a high discharge specific capacity of 13,070.2 mAh g-1 and extraordinary stability of 242 cycles with fixed specific capacity of 500 mAh g-1 under 200 mA g-1 . This effort could shed light on designing the promising phosphide electrocatalysts and contribute to developing highly effective LOBs cathode materials.