Liquid electrolytes gelation

Gelation of liquid electrolytes to obtain a gel that effectively penetrates into the pores of the 2 can be obtained by addition of appropriate additives such as small molecules,49 polymers, inorganic nanoparticles,49 50 and carbon nanotubes.51... 

Recently a dye-sensitized solar cell has been attracting a great deal of attention for converting solar energy into electricity [52]. Since this cell uses a redox electrolyte solution, it is important to solidify the liquid in order to stabilize the cell, but the task is not easy to achieve. To overcome this problem, solidification of the organic redox electrolyte solution by molten salts and gelator [53] or by polymer film [54,55] has been achieved. We have successfully used the polysaccharide solid to solidify the electrolyte solution [56,57], as later described in Sect. 4.1. 

Wang Zakeeruddin SM. Comte Exnarl. Gratzel M. Gelation of Ionic Liquid-based Electrolytes with Silica Nanoparticles for Quasi-solid-state Dye-sensitized Solar Cells, J. American Chemical society 2003,125, 1166-1167. 

Wang, P., Zakeeruddin, S.M., Comte, P., Exnar, I., and Graetzel, M. (2003) Gelation of ionic liquid-based electrolytes with silica nanoparticles for quasi-solid-state dye-sensitized solar cells. /. Am. Chem. Soc., 125, 1166-1167. 

In the first approach, PVP was used as gelling agent in electrolytes with ionic liquid. ° ° PVP was combined with HOOC(CH2) COOH (n = 4,7, 10,14), and the gelation was given by the reaction between the polymer and the dicarboxylic acid. Before gelation, the electrolyte based on the ionic liquid provided an efficiency of 5.2%.The gel electrolytes lead to solar cells with efficiencies of 3.4% to 4.4%, for carboxylic acid with different chain sizes, and the decrease in performance was associated with a decrease in the diffusion properties of the redox-active species. This decrease in... 

In several hydrophobic sols, especially those with flat or elongated particles it is possible to induce gelation by the addition of an amounf of electrolyte not quite sufficient to lead to a normal flocculation. Evidently the partly discharged particles arc attached to each other at a very few spots, still repelling each other on the main part of their surface and thus forming a network which immobilisies the included intermicellar liquid. 

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