Ultrafast synthesis of porous Fe3C/carbon hybrid materials via a carbothermal shock reactor for advanced energy storage applications

Abstract

Template-assisted pyrolysis enables the synthesis of Fe-based carbonaceous materials with a defined morphology and structure from iron–carbon precursors. However, conventional tangible templates are costly and have limited applications, and their removal process is time-consuming and environmentally harmful. Here, we employ an ultrafast heating technique (1 second to 1800 °C) using a carbothermal shock reactor to treat iron–carbon precursors. The high-density volatile vapor generated during the rapid pyrolytic carbonization of the precursor acts as a pore-forming agent, resulting in a porous carbon matrix. This high-density vapor also restricts the growth area of iron-based nanoparticles, promoting them to form ultrafine small sizes through confined synthesis. Finally, we successfully prepared the CTS–Fe–C-1800 hybrid material containing a porous carbon matrix and iron carbide nanoparticles and tested its electrochemical performance as a multifunctional electrode. As an electrode, the CTS–Fe–C-1800 supercapacitor (SC) exhibits a high specific capacity of 425.5 F g⁻¹ at 0.5 A g⁻¹. Moreover, the CTS–Fe–C-1800 flexible micro-supercapacitor (MSC), prepared using a PVA/KOH gel electrolyte and CTS–Fe–C-1800, demonstrates an impressive energy density of 71.49 W h kg g⁻¹ at 0.637 kW kg g⁻¹. Additionally, when employed as an anode electrode in a Li-ion battery (LIB), the CTS–Fe–C LIB maintains a capacity of 801.2 mA h g⁻¹ after 1000 cycles at 1 A g⁻¹, surpassing the performance of the majority of reported Fe–C anode electrodes.