Polylectrolyte- versus membrane-coated electrodes for energy production by Capmix salinity exchange methods
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AuthorFernández, M. Mar; Wagterveld, R. M.; Ahualli, Silvia; Liu, Fei; Delgado, Ángel V.; Hamelers, H. V. M.
Blue energyCapmix techniquesCDPDonnan potentialCarbon ElectrodesPolyelectrolyte coating
Fernández, M.M.; et al. Polylectrolyte- versus membrane-coated electrodes for energy production by Capmix salinity exchange methods. Journal of Power Sources, 302(20): 387-393 (2016). [http://hdl.handle.net/10481/38829]
SponsorshipMINECO FIS2013-47666-C3-1-R; Junta de Andalucía, PE2012-FQM0694; European Union 7th Framework Programme (FP7/2007–2013) under agreement No. 256868
In this paper we analyze the energy and power achievable by means of a re- cently proposed salinity gradient technique for energy production. The method, denominated soft electrode or SE, is based on the potential di erence that can be generated between two porous electrodes coated with cationic and anionic polyelectrolytes. It is related to the Capacitive Donnan Potential (CDP) tech- nique, where the electrical potential variations are mostly related to the Donnan potential, of ion-selective membranes in the case of CDP, and of the polyelec- trolyte coating in SE. It is found that although SE is comparable to CDP in terms of energy production, it presents slower rates of voltage change, and lower achieved power. The separate analysis of the response of positively and neg- atively coated electrodes shows that the latter produces most of the voltage rise and also of the response delay. These results, together with electrokinetic techniques, give an idea on how the two types of polyelectrolytes adsorb on the carbon surface and a ect di erently the di usion layer. It is possible to suggest that the SE technique is a promising one, and it may overcome the drawbacks associated to the use of membranes in CDP.