No 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.

No abstract

Lignin-based carbon fibers (LCFs) with graphitized structures decorated on their surfaces were successfully prepared using 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 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 50.2 F g−1 at 0.5 A g−1, power density of 644.9 kW kg−1, energy density of 15.7 Wh kg−1, and capacitance retention of 100% after 1500 cycles even without activation.

As an abundant bioresource of carbon, lignin has the potential to form carbon fibers (CFs), which can then be used as electrode materials in supercapacitors. However, most studies have only focused on the morphology of CFs, such as the specific surface area and pore-size distribution, while ignoring the influence of the carbon structure in CFs. In this study, Ni(acac)2 was used as a graphitization catalyst in CFs preparation and to further modify the morphology of the fibers. Meanwhile, the addition of Ni(acac)2 remarkably shortened the thermostabilization period from 76 h to 2.25 h, which significantly reduced the energy consumption. The resulting lignin-based activated carbon fibers (LACFs) with graphitized structures presented a controllable pore-size distribution and large surface areas up to 582.7 m2 g− 1. These LACFs were then used as electrode materials in supercapacitors, and the assembled devices displayed high energy and power densities of up to 22.1 Wh kg− 1 and 239 kW kg− 1, respectively, using organic electrolytes.