Facile synthesis of hollow Cu 3 P for sodium‐ion batteries anode

Combining metal to form metal phosphide is a promising strategy to address the fast capacity decay of P rooted from its low electronic conductivity and large volume changes upon cycling. Cu 3 P, which possesses a high theoretical gravimetric and volumetric capacity of 363 mAh·g −1 and 1028 Ah·L −1 and reasonable volume expansion of 156% during sodiation, was investigated as anode material in SIBs. Hollow‐structured Cu 3 P electrode delivers an initial de‐sodiation capacity of ~ 159.0 mAh·g −1 with high capacity retention of ~ 85.1% over 50 cycles at 0.2C rate and exhibits good rate performance, retaining 70% of the capacity when the current density increases from 0.2C to 1.6C. A 3 V‐class full cell consisting of P2‐Na 2/3 Ni 1/3 Mn 1/2 Ti 1/6 O 2 cathode and Cu 3 P anode was also assembled, which could achieve an energy density of ~ 189.3 Wh·kg −1 (based on the mass of both electrode materials) and average discharge voltage of ~ 2.91 V when cycled in 1.0–4.3 V at 0.1C.