The electrochemical and mass transport properties of TEABF4 in a nanoporous C material, obtained from silicon carbide, were studied by using single particles and a micro-electrode technique. The C particles (100 to 200μm) were studied by using cyclic voltammetry and potential step measurements. The effective diffusion coefficients (Deff) were calculated; starting from asymptotic solutions of Fick’s second law for short- and long-time regions. The results showed that cycling at low sweep rates was needed in order for the electrolyte to penetrate the inner porosity of the particles. The C material showed different electrochemical and mass transport properties depending upon the applied potential. At negative polarization, the results suggested that TEA+ was adsorbed at the pore wall, however, being transported very slowly within the pores. The average Deff after cycling at both positive and negative potentials was 1.1 x 10−8cm2/s, using the Cottrell relationship, and 1.5 x 10−8cm2/s, using the radial diffusion solution. The average value of Deff after cycling at negative potentials was 1.7 x 10−8cm2/s, using both mathematical solutions.

Determination of Diffusion Coefficients of BF4- Inside Carbon Nanopores Using the Single Particle Microelectrode Technique. M.Zuleta, P.Björnbom, A.Lundblad, G.Nurk, H.Kasuk, E.Lust: Journal of Electroanalytical Chemistry, 2006, 586[2], 247-59