Boosting lithium/sodium ion storage by synergistic effect between nanostructured Fe4N-Fe3C and 3D interconnected graphitic C3N4

The effective design of anode materials with superb physicochemical properties and optimized nano -architecture is regarded as a critical approach to improving the electrochemical performance of lithium/sodium-ion batteries (LIBs/SIBs). In this work, two-phase heterostructured Fe4N-Fe3C nanoparticles incorporated into the 3D interconnected graphitic -phase C3N4 (Fe4N-Fe3C@CN) are well designed combined molecular engineering with heterointerface engineering. Owing to the interconnected 3D structure, the produced Fe4N-Fe3C@CN material shows high Li+/Na+ ions storage performance with accommodated volume change and fast ion/electron transfer, leading to great cyclic stability and rate property. Meanwhile, the N heteroatoms and the dotted Fe4N-Fe3C heterointerface generate plentiful active sites and extra defects, promoting the boosted energy storage properties. By integration of these synergistic merits, our produced Fe4N-Fe3C@CN electrode delivers a high reversible specific capacity of 890.3 mAh g-1 after 2000 cycles at 2 A g-1 for LIBs and 224.8 mAh g-1 after 800 cycles at 1 A g-1 for SIBs. Furthermore, the quantitative kinetic analysis is carried out to illustrate the dominated capacitive energy storage contribution, further clarifying the improved ionic/electronic transfer capability. These achievements are of vital significance for the construction of anode materials for LIBs and SIBs with superior rate capability and long-term lifespan.