Pore Shape Affects Spontaneous Charge Redistribution in Small Pores

A complete understanding of charge redistribution (spontaneous movement of charge once the system has been placed on open-circuit) in porous materials is desirable because charge redistribution will affect the performance of devices incorporating porous electrodes. In this paper, a model pore based on the de Levie transmission line model is used to examine the effects of pore geometry on charge redistribution, including pore size, pore shape, and the presence of bottlenecks. Results highlight that pore geometry does affect the charge redistribution profile and emphasize the importance of the diameter of the pore mouth on charge redistribution. For cone, inverted cone, and cylindrically shaped pores having the same total resistance and capacitance, cone-shaped pores were able to accumulate the most charge. Results also indicate that the presence of a restrictive bottleneck beyond the pore mouth results in a charge redistribution profile with multiple slopes.