@misc{10481/25987,
year = {2013},
month = {7},
url = {http://hdl.handle.net/10481/25987},
abstract = {Capacitive energy extraction based on double layer expansion (CDLE) is the name of a new method
devised for extracting energy from the exchange of fresh and salty water in porous electrodes. It is based
on the change of the capacitance of electrical double layers (EDLs) at the electrode/solution interface
when the concentration of the bulk electrolyte solution is modified. The use of porous electrodes provides
huge amounts of surface area, but given the typically small pore size, the curvature of the interface and
EDL overlap should affect the final result. This is the first aspect dealt with in this contribution: we envisage
the electrode as a swarm of spherical particles, and from the knowledge of their EDL structure, we
evaluate the stored charge, the differential capacitance and the extracted energy per CDLE cycle. In all
cases, different pore radii and particle sizes and possible EDL overlap are taken into account. The second
aspect is the consideration of finite ion size instead of the usual point-like ion model: given the size of the
pores and the relatively high potentials that can be applied to the electrode, excluded volume effects can
have a significant role. We find an extremely strong effect: the double layer capacitance is maximum for a
certain value of the surface potential. This is a consequence of the limited ionic concentration at the particle-
solution interface imposed by the finite size of ions, and leads to the presence of two potential
ranges: for low electric potentials the capacitance increases with the ionic strength, while for large potentials
we find the opposite trend. The consequences of these facts on the possibility of net energy extraction
from porous electrodes, upon changing the solution in contact with them, are evaluated.},
organization = {Departamento de Física Aplicada, Grupo de Física de Interfases y Sistemas Coloidales,Facultad de Ciencias, Universidad de Granada.},
organization = {The research leading to these results received funding from the European Union 7th Framework Programme (FP7/2007-2013) under Agreement No. 256868. Further financial support to S.A. from Junta de Andalucía (Spain) Project PE-2008-FQM3993.},
publisher = {Elsevier},
keywords = {CapMix},
keywords = {Electric double layer expansion},
keywords = {Energy extraction from salinity exchange},
keywords = {Ionic size effects},
title = {Predictions of the maximum energy extracted from salinity exchange inside porous electrodes},
author = {Jiménez Olivares, María Luisa and Fernández, M. Mar and Ahualli Yapur, Silvia Alejandra and Iglesias Salto, Guillermo Ramón and Delgado Mora, Ángel Vicente},
}