Uniformly dispersed Co2P nanoparticles decorated hollow carbon spheres used as anode for sodium-ion batteries with superior long-term performance

Abstract

Utilizing a straightforward two-step hydrothermal approach, ZIF-67 is employed as a sacrificial template to effectively synthesize a highly efficient and stable Co₂P@HCS composite material for sodium ion storage, wherein Co₂P nanoparticles are uniformly distributed on the surface of hollow carbon spheres (HCS). The composite material possesses a distinctive multi-polar hollow architecture, integrating the synergistic benefits of its exterior Co₂P phase and interior HCS. CO₂P demonstrates considerable potential for sodium storage, and the hollow carbon spheres facilitates enhanced charge transfer and offer superior stability, effectively accommodating the volume variation of the Co₂P phase during the cycling process. Experimental outcomes reveal that the Co₂P@HCS electrode exhibits exceptional sodium storage performance. For instance, following 200 cycles at a current density of 250 mAh g⁻¹, the material achieves a capacity of 262.5 mAh g⁻¹; furthermore, even after 3000 cycles at a current density of 2500 mAh g⁻¹, it sustaines a capacity of 109.8 mAh g⁻¹. This synthetic method holds significant potential in the preparation of MOFs (metal-organic frameworks) and metal phosphide-based carbon composite materials, particularly for applications in energy storage.