Chemical activation of carbon mesophase pitches

• Published in: Journal of colloid and interface science Vol. 298; no. 1; pp. 341 - 347
• Main Authors: Mora, E., Blanco, C., Pajares, J.A., Santamaría, R., Menéndez, R.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 01-06-2006; Elsevier
• Subjects: Activation; Chemistry; Colloidal state and disperse state; Exact sciences and technology; General and physical chemistry; Immersion calorimetry; Mesophase; Porosity; Porous materials; Surface area; Immersion calorimetry; Mesophase; Activation; Porosity; Surface area; Pitch; Calorimetry; Immersion; Carbon
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2005.11.051

This paper studies the chemical activation of mesophase pitches of different origins in order to obtain activated carbons suitable for use as electrodes in supercapacitors. The effect that the activating agent (NaOH, LiOH, and KOH), the alkaline hydroxide/pitch ratio, and the activation temperature had on the characteristics of the resultant activated carbons was studied. LiOH was found to be a noneffective activating agent, while activation with NaOH and KOH yielded activated carbons with high apparent surface areas and pore volumes. The increase of the KOH/pitch ratio caused an increase of the chemical attack on the carbon, producing higher burnoffs and development of porosity. Extremely high apparent surface areas were obtained when the petroleum pitch was activated with 5:1 KOH/carbon ratio. The increase of the activation temperature caused an increase of the burnoff, although the differences were not as significant as those derived from the use of different proportions of activating agent.
N2 adsorption isotherms of carbons activated with different KOH-to-pitch ratios indicate that the increase of the proportion of KOH causes a significant increase in the development of porosity accompanied by the widening of the micropores.