Extracting Renewable Energy from a Salinity Difference Using a Capacitor

Brogioli, Doriano

doi:10.1103/physrevlett.103.058501

Cited by 392 publications

(424 citation statements)

References 15 publications

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“…After immersion in an aqueous gold nanoparticle solution, the particles were found to be excluded 4 from regions that were exposed for surface modification, consistent with exclusion of the liquid phase from the hydrophobic nanopores (Fig. 2a).…”

Section: Osmosis Membranes With Nanoscale Vapour Trapssupporting

confidence: 59%

Nanofluidic transport governed by the liquid/vapour interface

2014

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Section: Osmosis Membranes With Nanoscale Vapour Trapssupporting

confidence: 59%

Nanofluidic transport governed by the liquid/vapour interface

2014

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“…Both Donnan potentials increase in absolute value and on the other hand, since the charge on the particle surfaces is fixed, also the potential jump at the particle/solution interface ∆Ψ EDL increases in absolute value, as a consequence of the double layer expansion. 20 Being the increase of the latter of smaller significance, the exchange to a fresh solution results in a net increase of the surface potential, as shown in Fig. 1b-stage 2.…”

mentioning

confidence: 84%

Polyelectrolyte-coated carbons used in the generation of blue energy from salinity differences

Ahualli

Jiménez

Fernández

et al. 2014

Phys. Chem. Chem. Phys.

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In this work we present a method for the production of clean, renewable electrical energy from the exchange of solutions with different salinities. Activated carbon films are coated with negatively or positively charged polyelectrolytes by well-established adsorption methods. When two oppositely charged coated films are placed in contact with an ionic solution, the potential difference between them will be equal to the difference between their Donnan potentials, and hence, energy can be extracted by building an electrochemical cell with such electrodes. A model is elaborated on the operation of the cell, based on the electrokinetic theory of soft particles. All the features of the model are experimentally reproduced, although a small quantitative difference concerning the maximum opencircuit voltage is found, suggesting that the coating is the key point to improve the efficiency. In the used experimental conditions, we obtain a power of 12.1 mW/m 2 . Overall, the method proves to be a fruitful and simple approach to salinity-gradient energy production.Obtaining energy from salinity differences as those existing in river mouths 1,2 is a challenging task involving various complications. Although several attempts have been reported, 3-10 no one appears to prevail over the others, and a final choice has not been made. This applies as well to the recent proposals of the capmix group, 11 based on the change in the capacitance of the electrical double layer (EDL) at the interface between a conducting electrode and an ionic solution, when the salinity of the latter is modified.The capmix methods are not the only ones devised to harvest salinity difference energy. Desalination techniques operated in reverse are good candidates, in particular, pressureretarded osmosis (PRO), 8,12,13 and reverse electrodyalisis (RED). 3,14 In the former, fresh water is allowed to flow through a semipermeable membrane into a pressurized sea a Department of Applied Physics, School of Sciences, University of Granada, 18071, Granada, Spain. b Dipartimento di Scienze della Salute, Universit degli Studi di MilanoBicocca, Via Cadore 48, Monza (MB) 20900, Italy. * Corresponding author, E-mail: sahualli@ugr.es water chamber; this high-pressure solution is used to obtain electrical energy by depressurizing it through a turbine. In RED, concentrated salt solutions and fresh water flow through alternating cells which are separated by ion exchange membranes; the cells will be alternatively enriched in cations and anions, thus producing, respectively, negative and positive potentials at the corresponding electrodes. If the number of cells connected is large enough, the total voltage will be larger than the electrode reaction potential, and energy can be extracted. Although considerable advances have been produced in both techniques, [4][5][6][7]9,15 they are mostly at the laboratory scale. However, a recent analysis has shown that, at least for the river and sea water availabilities in the Dutch coast, a 1 MW RED plant could be competitive in the near f...

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“…Ions in the electrolyte rearrange to screen this interfacial charge over a length scale that is determined by the characteristics of the electrolyte. EDLs play a central role in colloidal 1 and polyelectrolyte science, 2 micro-and nanofluidics, 3 surface conductivity, 4 "blue energy" systems, 5 and in electric double-layer capacitors 6 that store energy electrochemically across the EDL. Detailed ion density profiles within EDLs have been measured experimentally using various techniques and materials, 7 e.g., from X-ray reflectivity measurements of liquid−liquid interfaces 8,9 and Langmuir monolayers.…”

Section: Introductionmentioning

confidence: 99%

Electric Double-Layer Structure in Primitive Model Electrolytes: Comparing Molecular Dynamics with Local-Density Approximations

et al. 2015

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ABSTRACT:We evaluate the accuracy of local-density approximations (LDAs) using explicit molecular dynamics simulations of binary electrolytes comprised of equisized ions in an implicit solvent. The Bikerman LDA, which considers ions to occupy a lattice, poorly captures excluded volume interactions between primitive model ions. Instead, LDAs based on the Carnahan− Starling (CS) hard-sphere equation of state capture simulated values of ideal and excess chemical potential profiles extremely well, as well as the relationship between surface charge density and electrostatic potential. Excellent agreement between the EDL capacitances predicted by CS-LDAs and computed in molecular simulations is found even in systems where ion correlations drive strong density and free charge oscillations within the EDL, despite the inability of LDAs to capture the oscillations in the detailed EDL profiles.

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Extracting Renewable Energy from a Salinity Difference Using a Capacitor

Cited by 392 publications

References 15 publications

Nanofluidic transport governed by the liquid/vapour interface

Nanofluidic transport governed by the liquid/vapour interface

Polyelectrolyte-coated carbons used in the generation of blue energy from salinity differences

Electric Double-Layer Structure in Primitive Model Electrolytes: Comparing Molecular Dynamics with Local-Density Approximations

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