P-doped CoSe2/FeSe2 heterojunction nanoparticles anchored on foam-like carbon skeleton as an ultrafast and stable sodium-ion storage anode

Abstract

P-doped CoSe₂/FeSe₂ heterojunction nanoparticles (2–10 nm) anchored on a three-dimensional porous foam-like carbon network were synthesized via a direct pyrolysis-blowing strategy followed by phosphorization/selenization process. This carbon network serves as a continuous pathway for electron conduction, enhances specific surface area, and alleviates electrode volume expansion during cycling. Specifically, P-doping further improves the electrical conductivity of CoSe₂/FeSe₂ nanoparticles, significantly accelerating electrochemical kinetics and enabling high specific capacities at elevated current densities. Benefiting from the unique nanostructure and atomic-level P-doping, the P-CoSe₂/FeSe₂(2:1)/C anode delivers prominent cycling stability (210.9 mAh g⁻¹ after 2000 cycles at 2000 mA g⁻¹) and exceptional rate capability (323.5 mAh g⁻¹ at 5000 mA g⁻¹). This work demonstrates that combining heterojunction engineering with heteroatom doping is an effective strategy to enhance the long-term cycling stability of sodium-ion battery anodes.