cell and surrounded by an electrolyte solution. The fixed Sorption of LiCl, diffusion of Li / ions, and diffusion of water charges of the resin were thought to be uniformly spread have been studied as a function of the salt concentration in a over the surfaces of the spheres. The sorption of salt can be synthesized cation-exchange resin bearing sulfonic acid groups. calculated in this model by solving the Poisson-Boltzmann The Li / diffusion shows a maximum in the salt concentration equation within the spherical cell. Second, we used the dependence reflecting on one side the enhanced diffusion due to model of Glueckauf (4, 5) which allows the fixed charges screening of the fixed charges on the charged matrix and on the to be nonuniformly distributed throughout the resin.
other hindered diffusion by shrinking of this matrix. A theoretical
The mobilities of ions and water molecules in the resins analysis is given in which the resin is visualized as being composed of spherical cells with the charged spheres placed in the centers. will be reduced due to the exclusion of the moving particles Also, the phenomenological approach of Glueckauf (4, 5) is apfrom the volume occupied by the polymer network. This plied. The spherical cell model gives a semi-quantitative prediction implies an increase in path length denoted as tortuosity. The of the observed sorption and diffusion. The experimental results tortuosity is dependent on the degree of swelling, which is agree nicely with the semi-empirical power laws of Glueckauf. a function of properties like crosslink density (or in terms