Core-shell Fe2N@amorphous carbon nanocomposite-filled 3D graphene framework: An additive-free anode material for lithium-ion batteries

Abstract

Among various anode materials, Fe2N becomes a “shining star” owing to its high electrical conductivity and large specific capacity. However, its dramatic volume variation and air sensitive severely limit its application. To address these obstacles, herein, we synthesized a dual-carbon protected Fe2N composite (abbreviated as Fe2N@AC@rGO) by a reliable electrostatic self-assembly strategy. The amorphous carbon (AC) shell and flexible reduced graphene oxide (rGO) framework can promise stable electrode structure, reduced electrode resistance and enhanced electrochemical reaction kinetics. Benefiting from the engineered structure merits and synergistic effects between different counterparts, the resultant Fe2N@AC@rGO anode delivers a long-term cycle stability (98.9% capacity retention, 500th cycle vs. 3rd cycle, at 0.5 A g−1) and remarkable rate capability (303 mA h g−1 at 10 A g−1, retains 57% of the value at 0.2 A g−1) even totally free of any conductive additives. Supported by the detailed analysis of the recovered electrode after cycling, the superior cyclability can be largely attributed to the stable electrochemical reaction interface and robust electrode structure. The outstanding rate performance can be well-interpreted from the enhanced contributions of surface-capacitive behaviors and accelerated electrons and ions transfer kinetics.