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Porous carbon materials have demonstrated exceptional performance in various energy and environment-related applications. Recently, research on supercapacitors has been steadily increasing, and porous carbon materials have emerged as the most significant electrode material for supercapacitors. Nonetheless, the high cost and potential for environmental pollution associated with the preparation process of porous carbon materials remain significant issues. This paper presents an overview of common methods for preparing porous carbon materials, including the carbon-activation method, hard-templating method, soft-templating method, sacrificial-templating method, and self-templating method. Additionally, we also review several emerging methods for the preparation of porous carbon materials, such as copolymer pyrolysis, carbohydrate self-activation, and laser scribing. We then categorise porous carbons based on their pore sizes and the presence or absence of heteroatom doping. Finally, we provide an overview of recent applications of porous carbon materials as electrodes for supercapacitors. [ABSTRACT FROM AUTHOR]

Carbon nanofiber nonwovens (CFN) are powerful electrode materials with exceptional performance in energy storage devices, such as batteries and supercapacitors. Small fiber‐diameters together with hierarchical porosity endow CFN‐electrode materials with large surface areas and high electrical capacitance. Porosity of the fiber surface is often realized by corrosive activation methods such as wet‐etching or using oxidative gases at elevated temperatures. In this study, we present a chemical‐free, environmental‐friendly, and easily controllable surface activation method using an atmospheric pressure plasma‐jet. We investigate the best instant for activation along the process chain and show that the surface area of nanofiber nonwovens can be tailored by adjusting the plasma exposure‐dose. Plasma‐activated CFNs show an almost 20‐fold increase in capacitance (CspPJ = 10.1 F/g) in an electrochemical supercapacitor setup compared to nonactivated CFN (CspnoPJ = 0.55 F/g). [ABSTRACT FROM AUTHOR]

Carbon nanofibers derived from lignocellulosic materials have become the most prevalent free-standing electrode material for supercapacitors due to their renewable and sustainable nature. This study used Arenga pinnata bunches (APB) as raw material for hemicellulose compounds to produce carbon electrodes through carbonization processes at 650 °C, 700 °C, 750 °C, and 800 °C, in the presence of flowing N2 gas. The variations in carbonization temperature resulted in carbon electrodes with surface morphology having a nanofiber structure with micro-meso pore distribution. According to the results, the carbonization temperature of 700 °C (APB-700) is the optimum temperature for producing electrode surface morphology with a combination of nanofiber, micro-and mesopore distributions, as well as specific surface area, specific capacitance, energy density, and power density of 1231.896 m2 g−1, 201.6 F g−1, 28.0 Wh kg−1, and 109.5 W kg−1, respectively, for the two electrode systems. This shows the combination of nanofibers and the distribution of micro-and mesopores produced with variations in carbonization temperature has the capacity to improve the performance of supercapacitor cells. Therefore, carbon nanofibers derived from Arenga pinnata bunches have the potential to be used as free-standing electrode materials for supercapacitors without employing doping, binder, electrospinning, and heteroatom template methods. [ABSTRACT FROM AUTHOR]

Free-standing carbon nanofibrous membranes are prepared by carbonization and H 2 O 2 activation of electrospun polyimide nanofibrous membranes. The green and facile H 2 O 2 activation method not only regulates the pore structure of carbon nanofibers but also introduces rich oxygen species, rendering a hierarchically porous and heteroatom-doped carbon electrode for supercapacitors. The optimal electrode (PI800-8) shows a high specific capacitance of 339.9 F g−1 (0.5 A g−1, 6 M KOH electrolyte) and excellent cycle durability with a capacitance retention of 98.4 % after 50,000 cycles (5 A g−1). Particularly, a non-aqueous symmetric supercapacitor assembled with 1 M Et 4 NBF 4 electrolyte shows a high operating voltage of 2.8 V, and delivers the maximum energy/power density of 37.3 Wh kg−1 and 28.0 kW kg−1, respectively. The H 2 O 2 activation method provides a green, efficient, and versatile strategy to improve the pore properties and chemical compositions of porous carbon materials towards energy applications. [Display omitted] • The N/O-codoped carbon nanofibrous membranes were prepared by commercial electrospun polyimide nanofibrous membranes. • The green H 2 O 2 activation was proposed to ameliorate the pore and chemical properties of carbon nanofibrous membranes. • Excellent comprehensive performance was presented for both aqueous/non-aqueous symmetric supercapacitor. [ABSTRACT FROM AUTHOR]