Co₃O₄-Induced Na₂CO₃-Rich SEI Film on an FeNCN Electrode with Promoted Loading and High-Rate Na-Storage Performance

Iron carbodiimide (FeNCN) often suffers from unstable interfacial structure with an unexpected failure of Na-ion storage performance. In this work, Co₃O₄ particles were deposited on the surface of FeNCN. This Co₃O₄ nanolayer led to the formation of a Na₂CO₃-rich inorganic component SEI film to enhance the stability of a promoted-loading FeNCN electrode interface with fast Na⁺ migration pathway. Benefitting from this strategy, the FeNCN electrode could present a capacity retention rate of 99.95% per cycle after 1500 cycles at 1 A g^-1. The design of interfacial structure in a promoted-loading electrode could be a reference for stable and high-rate performance of carbodiimide-based materials.