1 research outputs found
Aqueous-Processed, High-Capacity Electrodes for Membrane Capacitive Deionization
Membrane capacitive deionization
(MCDI) is a low-cost technology
for desalination. Typically, MCDI electrodes are fabricated using
a slurry of nanoparticles in an organic solvent along with polyvinylidene
fluoride (PVDF) polymeric binder. Recent studies of the environmental
impact of CDI have pointed to the organic solvents used in the fabrication
of CDI electrodes as key contributors to the overall environmental
impact of the technology. Here, we report a scalable, aqueous processing
approach to prepare MCDI electrodes using water-soluble polymer polyÂ(vinyl
alcohol) (PVA) as a binder and ion-exchange polymer. Electrodes are
prepared by depositing aqueous slurry of activated carbon and PVA
binder followed by coating with a thin layer of PVA-based cation-
or anion-exchange polymer. When coated with ion-exchange layers, the
PVA-bound electrodes exhibit salt adsorption capacities up to 14.4
mg/g and charge efficiencies up to 86.3%, higher than typically achieved
for activated carbon electrodes with a hydrophobic polymer binder
and ion-exchange membranes (5–13 mg/g). Furthermore, when paired
with low-resistance commercial ion-exchange membranes, salt adsorption
capacities exceed 18 mg/g. Our overall approach demonstrates a simple,
environmentally friendly, cost-effective, and scalable method for
the fabrication of high-capacity MCDI electrodes