CONICET | Buscador de Institutos y Recursos Humanos

Electrochemical double layer capacitors use, as electrodes, conductive porous materials. Among them, carbon materials are widely used due to their low cost, good conductivity and negligible corrosion. It is possible to produce monolithic porous dry resins, which give porous carbon by pyrolysis, by condensation of resorcinol and formaldehyde in the presence of a sol-gel stabilizer, such as a cationic surfactant,[1] or a polyelectrolyte [2]. However, monolithic materials show large specific capacitances (> 150 F/g) but slow responses due to the large length of the pores.[3] A way to overcome that is to produce micro/nanoparticles and assemble into active layers. In this communication is described the synthesis of porous carbon particles by: ii) milling and sieving of monolithic carbon; ii) condensation inside inverse (water in oil) emulsions; iii) nucleation and growth of the sol-gel in dilute solutions. The resin particles are carbonized at 800 oC in inert atmosphere and the carbon particles are characterized by SEM, TEM, N2, methylene blue and I2 adsorption. The particles are assembled into films either by dip coating of particles dispersion in Nafion® solution or by layer-by-layer self assembly with a cationic polyelectrolyte. The study of the electrochemical properties reveal that chemical methods does not produce isotropic particles but spheres with a compact shell surrounding the open core. On the other hand, the particulate material shows faster response than the monolithic one. References [1] M.M. Bruno, N.G. Cotella, M.C. Miras, T. Koch, S. Seidler, C. Barbero Colloids and Surfaces A: Physicochemical and Engineering Aspects, 358(2010)13-20 [2] M.M. Bruno, N.G. Cotella, M.C. Miras, C.A. Barbero Colloids and Surfaces A: Physicochemical and Engineering Aspects, in Press March 2010, doi:10.1016/j.colsurfa.2010.03.032 [3] C. Barbero, Phys. Chem. Chem. Phys., 7(2005)1885 - 1899

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