Electrode kinetics in the “capacitive mixing” and “battery mixing” techniques for energy production from salinity differences

Marino, Massimo; Misuri, L.; Ruffο, Riccardo; Brogioli, Doriano

doi:10.1016/j.electacta.2015.07.069

Cited by 29 publications

(26 citation statements)

References 38 publications

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“…We showed that the manganese oxide was necessary for power production by using a control cell containing composite electrodes that contained no manganese oxide (data not shown) and did not generate any power. These measured average power densities are consistent with other recent studies (0.015 to 3.8 W/m 2 ) ,,, that used a similar cell architecture but different electrode materials and sodium chloride concentrations.…”

Section: Resultssupporting

confidence: 91%

Surveying Manganese Oxides as Electrode Materials for Harnessing Salinity Gradient Energy

Fortunato

Peña

Benkaddour

et al. 2020

Environ. Sci. Technol.

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The potential energy contained in the controlled mixing of waters with different salt concentrations (i.e., salinity gradient energy) can theoretically provide a substantial fraction of the global electrical demand. One method for generating electricity from salinity gradients is to use electrode-based reactions in electrochemical cells. Here, we examined the relationship between the electrical power densities generated from synthetic NaCl solutions and the crystal structures and morphologies of manganese oxides, which undergo redox reactions coupled to sodium ion uptake and release. Our aim was to make progress toward developing rational frameworks for selecting electrode materials used to harvest salinity gradient energy. We synthesized 12 manganese oxides having different crystal structures and particle sizes and measured the power densities they produced in a concentration flow cell fed with 0.02 and 0.5 M NaCl solutions. Power production varied considerably among the oxides, ranging from no power produced (β-MnO 2 ) to 1.18 ± 0.01 W/m 2 (sodium manganese oxide). Power production correlated with the materials' specific capacities, suggesting that cyclic voltammetry may be a simple method to screen possible materials. The highest power densities were achieved with manganese oxides capable of intercalating sodium ions when their potentials were prepoised prior to power production.

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Section: Resultssupporting

confidence: 91%

Surveying Manganese Oxides as Electrode Materials for Harnessing Salinity Gradient Energy

Fortunato

Peña

Benkaddour

et al. 2020

Environ. Sci. Technol.

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“…Salinity differences between seawater and freshwater contain an enormous amount of entropic energy, which – if harvested – could produce approximately 1 TW of renewable electricity from coastal sites worldwide . Several salinity-gradient energy (SGE) technologies have been developed to convert this energy into electrical power, including pressure-retarded osmosis (PRO), − reverse electrodialysis (RED), ,− and capacitive mixing (CapMix). − In PRO, electrical power is produced by creating pressure differences between two waters with different salinities using semipermeable membranes. In RED, potential differences developed across an array of ion-exchange membranes produce electrical power using electrodes and soluble redox-active compounds.…”

Section: Introductionmentioning

confidence: 99%

“…Several CapMix approaches have been developed with different reactor configurations and electrode materials. Capacitive energy extraction based on double layer expansion (CDLE) uses two porous carbon electrodes that undergo capacitive charging/discharging reactions, which produce power by exploiting the concentration-dependent double layer thickness and subsequent voltage rise and fall at each electrode. − Generating electrical power using CDLE has major challenges, including charge leakage, low power densities (0.05 W m –2 ), and intermittent power production . Producing electrical power using capacitive energy extraction based on Donnan Potentials (CDPs) is similar to CDLE, except that potentials are developed across ion-exchange polymers or membranes placed on the surface of carbon electrodes. − CDP has multiple advantages over CDLE, including higher power densities (∼0.2 W m –2 ) through external electrode charging and continuous power production using flow electrodes. , The major disadvantage of CDP is that, like RED, it requires expensive ion-exchange membranes.…”

Section: Introductionmentioning

confidence: 99%

Harvesting Energy from Salinity Differences Using Battery Electrodes in a Concentration Flow Cell

Kim

Rahimi

Logan

et al. 2016

Environ. Sci. Technol.

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Salinity-gradient energy (SGE) technologies produce carbon-neutral and renewable electricity from salinity differences between seawater and freshwater. Capacitive mixing (CapMix) is a promising class of SGE technologies that captures energy using capacitive or battery electrodes, but CapMix devices have produced relatively low power densities and often require expensive materials. Here, we combined existing CapMix approaches to develop a concentration flow cell that can overcome these limitations. In this system, two identical battery (i.e., faradaic) electrodes composed of copper hexacyanoferrate (CuHCF) were simultaneously exposed to either high (0.513 M) or low (0.017 M) concentration NaCl solutions in channels separated by a filtration membrane. The average power density produced was 411 ± 14 mW m–2 (normalized to membrane area), which was twice as high as previously reported values for CapMix devices. Power production was continuous (i.e., it did not require a charging period and did not vary during each step of a cycle) and was stable for 20 cycles of switching the solutions in each channel. The concentration flow cell only used inexpensive materials and did not require ion-selective membranes or precious metals. The results demonstrate that the concentration flow cell is a promising approach for efficiently harvesting energy from salinity differences.

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“…The ability of intercalation materials to store cations upon electrical chargingh as been exploited in new,p romising techniques in which ions are captured from as olutionand released into ad ifferent one. This electrochemical ion pumping has been proposed for water desalination; [1] concentrating lithium salts; [2][3][4][5] and application in the mixing entropyb attery, [6][7][8][9][10] which, analogously to capacitive mixing, [11][12][13] produces clean electricale nergy by capturing salt from sea water and releasing it into river water.T hese applications could address some major worldwide concerns,i ncluding fresh-water shortage due to population growth, [14] availability of lithium, [15] and environmental pollution occasioned by use of fossil fuels. Intercalation materials have also been used in batteries;arecent application is for batteries based on mixed aqueous electrolytes.…”

Section: Introductionmentioning

confidence: 99%

Intercalation into a Prussian Blue Derivative from Solutions Containing Two Species of Cations

et al. 2017

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Reversible mixed-ion intercalation in nonselective host structures has promising applications in desalination, mixed-ion batteries, wastewater treatment, and lithium recovery through electrochemical ion pumping. One class of host compound that possesses many of the requirements needed for such applications (cost effectiveness, fast ion kinetics, and stability in an aqueous medium) includes the Prussian blue derivatives. Herein, the fundamental process of intercalation of multiple cations is studied at the thermodynamic level by means of galvanostatic cycling. Nickel hexacyanoferrate is focused upon because of its stability and low potential for electrochemical process relative to other hexacyanoferrates. Various cations can be intercalated; large cations (K and NH ) are intercalated at higher potentials than those of smaller cations (Na ). When mixtures of cations are present in solution, the potential profile is not qualitatively altered with respect to single-salt solutions, but the potential of (de-)intercalation is shifted; a simple thermodynamic model is introducted that is able to predict the potential and distribution at which intercalation takes place.

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Electrode kinetics in the “capacitive mixing” and “battery mixing” techniques for energy production from salinity differences

Cited by 29 publications

References 38 publications

Surveying Manganese Oxides as Electrode Materials for Harnessing Salinity Gradient Energy

Surveying Manganese Oxides as Electrode Materials for Harnessing Salinity Gradient Energy

Harvesting Energy from Salinity Differences Using Battery Electrodes in a Concentration Flow Cell

Intercalation into a Prussian Blue Derivative from Solutions Containing Two Species of Cations

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