Overview on the use of surfactants for the preparation of porous carbon materials by the sol-gel method: applications in energy systems

Abstract Porous carbon materials attract great interest because of the wide range of applications in electrochemical energy systems, especially in the case of structured and porosity-tuned carbons prepared by template-assisted methods. The use of surfactant prevents the collapse of the porous structure during the air-drying stage in the sol-gel process, which is regarded as a critical stage in this method. This work offers an overview on the use of surfactants as templates for the manufacture of tunable porous carbon materials by the sol-gel method mainly using the polymerization reaction of resorcinol (R) and formaldehyde (F). The use of surfactants avoids the application of other economically disadvantaged drying techniques such as supercritical fluids and freeze-drying. The surfactant-assisted sol-gel methods reported in the literature for the fabrication of porous carbons are widely discussed, as well as the potentiality of the synthesized materials as electrodes in electrochemical systems, which greatly depends on the final porous structure. Besides, this work offers information on hybrid methods in which surfactants are used not only for the fabrication of porous carbon materials with mesoporous/microporous structure but also for the development of advanced structures and composites, including nanomaterials with enhanced properties. Finally, future prospects in the synthesis of carbon materials prepared by surfactant-assisted sol-gel method are presented.