In situ FeF3 coating on FeNCN to stabilize discharged products Fe0 for enhanced loading and high-rate Na storage performance

The instability of the interfacial structure during the synthesis of iron carbodiimide (FeNCN) leads to a decline in its electrochemical performance during cycling. By depositing FeF 3 particles on the surface of FeNCN, the in-situ transformation of this FeF 3 nanolayer into a FeF 2 nanolayer effectively utilizes the discharge product Fe 0 . This process constructs a mechanically stable sandwich-structured SEI film, thereby enhancing the stability of the FeNCN electrode interface. Consequently, the FeNCN electrode exhibits a capacity of 350.54 mAh g −1 after 2000 cycles at 2 A g −1 , with a capacity retention rate of 99.54 %. This strategy provides crucial theoretical and technical insights for regulating carbodiimide-based materials to achieve stable, long-cycle performance in electrode materials.