Metal–Organic Frameworks-Derived Porous Yolk–Shell MoP/Cu₃P@carbon Microcages as High-Performance Anodes for Sodium-Ion Batteries

Transitional metal phosphides (TMPs) anode materials usually have large volume change and weak diffusion kinetics, leading to poor cycle stability. Combining TMPs with conductive carbon matrix has been widely used to boost sodium storage. However, it still needs to make efforts in the rational and facile design of nano/micro-structural TMPs/carbon hybrid anode material. Herein, a MOFs-derived strategy is developed to synthesize porous yolk–shell MoP/Cu₃P@carbon microcages (MoP/Cu₃P@C) through in situ and confined phosphidation reaction as a high-performance sodium-ion batteries anode. This yolk–shell structure can offer adequate internal space to buffer the large volume expansion, shorten diffusion distance, and create more active sites of Na⁺. Especially, the Cu nanoparticles generated from Cu₃P have remarkable electronic conductivity of 5.7 × 10⁷ S m⁻¹ (the second most conductive metal) to benefit transporting electrons. And the introduction of Mo (MoP has high theoretical capacity of 633 mA h g⁻¹) can enhance the reversible capacity of the whole anode material. Therefore, these porous yolk–shell MoP/Cu₃P@carbon microcages possess excellent reversible capacity of 307.8 mA h g⁻¹ at 1.0 A g⁻¹ and extraordinary cycle stability of 132.1 mA h g⁻¹ at 5.0 A g⁻¹ even after 6000 cycles.