Harvesting energy from salinity differences using battery electrodes in a concentration flow cell

Taeyoung Kim, Mohammad Rahimi, Bruce Ernest Logan, Christopher Aaron Gorski

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

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.

Original languageEnglish (US)
Pages (from-to)9791-9797
Number of pages7
JournalEnvironmental Science and Technology
Volume50
Issue number17
DOIs
StatePublished - Sep 6 2016

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Energy harvesting
electrode
salinity
Electrodes
membrane
energy
Ion selective membranes
Membranes
precious metal
Precious metals
Seawater
Copper
electricity
Carbon
Electricity
copper
seawater
battery
ion
carbon

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Environmental Chemistry

Cite this

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abstract = "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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Harvesting energy from salinity differences using battery electrodes in a concentration flow cell. / Kim, Taeyoung; Rahimi, Mohammad; Logan, Bruce Ernest; Gorski, Christopher Aaron.

In: Environmental Science and Technology, Vol. 50, No. 17, 06.09.2016, p. 9791-9797.

Research output: Contribution to journalArticle

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