Charging dynamics of the electric double layer in porous media

Electric double layer in porous media is studied with direct numerical simulations of the Nernst-Planck-Poisson equation. The time evolution of the charging process of the electric double-layer along a straight pore is first studied, and confirm that the time evolution obeys a power law of the exponent 1/2. We find that the diffusion constant increases effectively by the effect of the width of the pore. Next it is found that the time evolution of the charging process in fractal porous media obeys a power law, and the exponent alpha is related to the fracton dimension. Finally, we propose a coupled map lattice model for the creation of pore structures by gas activation processes, and perform numerical simulation of the charging dynamics of the electric double layer.