Interface engineering on cobalt selenide composites enables superior Alkali-Ion storage

Cobalt selenide (CoSe₂), a promising anode material for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs), still encounters the undesirable rate capability and cycling stability. Interface engineering offers a useful strategy to boost the electrochemical performance of electrode materials. Herein, an interface engineered material based on CoSe₂/ZnSe nanoparticles confined in the hierarchical branched architecture constructed by N-doped carbon-nanotube-grafted nanorods (CoSe₂/ZnSe@NC-NT/NRs) is developed, which delivers extraordinary Li⁺/Na⁺ storage capability as reflected in LIBs and SIBs. Large energy band gap difference between CoSe₂ and ZnSe builds a strong built-in electric field at as-engineered interfaces. The emergence of built-in electric field can reduce the migration barriers of Li⁺/Na⁺ at the interfaces to facilitate the charge transfer behavior and improve the reaction kinetics in bulk phase. Additionally, carbon framework with hierarchical branched architecture can furnish numerous pathways for ions transport and alleviate the structural collapse. The present work could guide the future designing of electrode materials by rational interface engineering for high-performance anode of alkali-ion batteries.