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.

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Activated carbon with high porosity and controlled pores structure are widely applied as supercapacitor electrodes biomass derived from sago midrib (PS). Activated carbon based on sago midrib without chemical agent and using chemical agent ZnCl2 and NaOH by a concentration 0,5 M has been fabricated with a purpose to produce distribution of mesopores and micropores. Samples were carbonized at temperature 600°C using N2 gas followed by a physical activation process using CO2 gas at temperature of 700°C. The highest mass loss percentage of carbon electrode PS-ZnCl2 was 51,6% Microstructure analysis shows that amorphous structure for the activated carbon electrodes is shown by the presence of the peaks of 2θ around 240 and 440 with the highest Lc presented by ZnCl2. SEM characterization showed the domination of mesopores and a few of micropores presented by ZnCl2. EDX characterization showed the highest atomic carbon percentage is 90,27%. Specific capacitance was determined by cyclic voltammetry method and found the highest in PS-ZnCl2 was 138 F/g. The result from the physical and chemical properties, ZnCl2 is the best chemical agent from biomass-derived sago midrib for the best performance of supercapacitor cells.

This study aimed to prepare Veitchia merilli coir (VMC) through pre-carbonisation process, followed by chemical activation using potassium hydroxide as an activating agent. The experiment was conducted under different pyrolytic physical activation temperatures of 650, 700, and 750 °C with the code VMS-650, VMS-700, and VMS-750 for each sample. Physical activation methods develop or modify the pore structure, specific surface area, and microstructure of activated carbon. Furthermore, the prepared VMCs were characterised using X-ray diffraction, Fourier transform infrared, scanning electron microscope, energy dispersive X-ray, and cyclic voltammetry with a symmetrical two-electrode system in 1 M H2SO4 solution. The microstructure analysis showed that the VMC carbon electrode has an amorphous structure with two broad peaks at 2θ angles around 26° and 44° corresponding to the (002) and (100) planes, with the L c VMS-700 having a value of 16.007 nm. The VMC electrode has a C≡C carbon bond as a functional group, which extends in bands from 2311.79 to 2373.51 cm−1. Meanwhile, the VMS-700 electrode shows a combined surface morphology of nanofibers as well as mesopores, and the energy dispersive X-ray results showed carbon content of 92.83%. The electrochemical properties of supercapacitor cells indicated this electrode had the highest specific capacitance value of 264.2 F g−1. From the obtained results, the respective physical and electrochemical properties of the carbon electrodes and supercapacitor cells showed that the activated VMC-700 at 700 °C is the optimum temperature to produce the best performance compared to 650 and 750 °C.