Fabrication of Graphitized Carbon Fibers from Fusible Lignin and Their Application in Supercapacitors

Abstract

Lignin-based carbon fibers (LCFs) with graphitized structures decorated on their surfaces were successfully prepared using the simultaneous catalyst loading and chemical stabilization of melt-spun lignin fibers, followed by quick carbonization functionalized as catalytic graphitization. This technique not only enables surficial graphitized LCF preparation at a relatively low temperature of 1200 °C but also avoids additional treatments used in conventional carbon fiber production. The LCFs were then used as electrode materials in a supercapacitor assembly. Electrochemical measurements confirmed that LCF-0.4, a sample with a relatively low specific surface area of 89.9 m2 g−1, exhibited the best electrochemical properties. The supercapacitor with LCF-0.4 had a specific capacitance of 10.7 F g−1 at 0.5 A g−1, a power density of 869.5 W kg−1, an energy density of 15.7 Wh kg−1, and a capacitance retention of 100% after 1500 cycles, even without activation.

Amorphous Alumina Thin Films Deposited on Carbon Microfibers As Interface Layer for Thermal Oxidation Barriers

“…Furthermore, the orientation of the crease of the singular rips observed on the microfiber edges indicates a pressure force stemming from the microfiber at the carbonaceous interface. As the presence of transition metal catalysts such as Al 3+ was previously reported to lower the temperature of graphitization, these local overpressures could plausibly be due to events related to surface graphitization . The migration of volatile carbon oxide through the coating during annealing could have led to the appearance of crystalline aluminum oxide-based outgrowths, as was previously reported on protocols of fabrication of fiber-templated ceramic thin tubes …”

“…As the presence of transition metal catalysts such as Al 3+ was previously reported to lower the temperature of graphitization, these local overpressures could plausibly be due to events related to surface graphitization. 61 The migration of volatile carbon oxide through the coating during annealing could have led to the appearance of crystalline aluminum oxide-based outgrowths, as was previously reported on protocols of fabrication of fiber-templated ceramic thin tubes. 62 To further discuss the cracked coatings, the thermal procedure was repeated in an inert atmosphere, in order to preserve the underneath carbon microfiber, showcased in Figure 5.…”