Carbon intermediate boosted Fe-ZIF derived α-Fe₂O₃ as a high-performance negative electrode for supercapacitors

Earth-abundant Fe₂O₃ is a promising material for the negative electrode of supercapacitors by virtue of its wide potential windows. However, the unsatisfactory electrical conductivity and poor ionic diffusion rate within Fe₂O₃ results in degraded electrochemical performance. In this work, to address these issues, we demonstrate an easy method to synthesize Fe-based zeolitic imidazolate framework (Fe-ZIF) derived α-Fe₂O₃@C with remarkable supercapacitive properties. The as-obtained α-Fe₂O₃@C electrode, with the particular benefit of dispersed distribution of carbon, enabling fast electrochemical response, presents a prospective specific capacitance of 161 Fg^-1 at a current density of 1 Ag^-1. Furthermore, by using the α-Fe₂O₃@C architecture as the negative electrode, we fabricated a supercapacitor with Na_0.5MnO₂ as the positive electrode. Our supercapacitor shows a high energy density of 25 Whkg^-1, while the corresponding power density is 2400 Wkg^-1 at a current density of 2 Ag^-1.