Efficient PEDOT Electrode Architecture for Continuous Redox-Flow Desalination

Abstract

Both low-energy consumption and high salt removal rate are highly required in the electrochemical desalination. In this work, a conducting polymer poly(3,4-ethylene-dioxythiophene), i.e., PEDOT, is electrochemically decorated on a graphite foil as an electrode material of redox-flow desalination (RFD). At a current density of 2 mA•cm −2 , the energy consumption of the RFD is reduced to 38.1 kJ•mol −1 with PEDOT-modified electrodes, compared with 154.5 kJ•mol −1 using a bare graphite electrode. Meanwhile, the salt removal rate is enhanced to 1.54 μmol•cm −2 •min −1 using the PEDOT electrode from 1.11 μmol•cm −2 •min −1 in the bare graphite electrode. The PEDOT electrodes can also provide excellent cycling stability. The improved performance may be due to the promising conductivity and porous structure of PEDOT, which would supply more active sites between the electrode and the redox electrolyte. The current research provides an electrochemical desalination strategy with low energy consumption and high salt removal rate, which is significant for the development of RFD technology.

Smart Energy Clays: Chemical Vapor Deposition of PEDOT in Expanded Vermiculite Blocks for Electrochemical Energy Storage

“…The peaks located at 989 and 576 cm –1 correspond to the deformation of oxyethylene. The peaks at 852 and 696 cm –1 are attributed to C–S–C symmetric stretching and C–O–C symmetric stretching. , It can be confirmed from both FT-IR spectra and Raman spectra that PEDOT is successfully synthesized on the surface of EVMT. As the XRD characterization plot shows, EVMT diffraction peaks are observed at 2θ = 8.89° and 2θ = 27.16° .…”

“…The peaks detected at 1195, 1135, and 1073 cm –1 correspond to the characteristic structure of the ethylenedioxy ring (C–O–C). Additionally, the vibrational modes identified at 913, 807 and 745 cm –1 can be assigned to the thiophene ring structure (C–S–C). − The peaks at 1493 and 1442 cm –1 in the Raman spectra of PEDOT/EVMT-180 are assigned for the asymmetric stretching of C α C β (Figure b). What is more, the peaks at 1258 and 1368 cm –1 indicate the presence of bonds C α –C α and C β –C β .…”

Energy Consumption in Capacitive Deionization for Desalination: A Review

“…Moreover, in addition to liquid solutions, the energy consumption can also be enhanced by optimization of the solid electrode materials. Ramalingam et al [ 102 ] replaced graphite electrodes in a redox flow cell with the conductive polymer material 3,4-ethylene-dioxythiophene (PEDOT) with a rough surface. With a constant current density of 2 mA·cm −2 , the energy consumption dramatically decreased by 75.34% to 0.18 Wh·g NaCl −1 and the salt removal rate improved by 38.74%.…”

Donor–Node–Acceptor Ambipolar Conducting Polymer Electrode Materials for Wide-Voltage and High-Stability Supercapacitors

“…Extending the operating voltage of ambipolar electrode material is still the research direction of supercapacitors, in which the selection of donor and acceptor and the connection between them are important. Poly­(3,4-ethylenedioxythiophene) (PEDOT) is often used as an electrode material for p-type supercapacitors because of its stable oxidation state and good electrical conductivity. , As its monomer, 3,4-ethylenedioxythiophene (EDOT) is often used as a donor unit of the D-A ambipolar polymer. Molecules containing imide groups, such as phthalimide, naphthalimide, perylene imide, and isoindigo, are often used as acceptor units, because the carbonyl group on the molecular structure can undergo a redox reaction similar to that of a battery.…”