Polymer-coated composite anodes for efficient and stable capacitive deionization

•Polymer-coated carbon anodes were prepared for CDI testing.•Improved salt removal using polymer-coated anodes was observed.•Parasitic reactions were discussed based on the pH and steady-state current.

In the contemporary literature, diminished salt removal in a CDI device is primarily due to carbon oxidation at the anode in aqueous solutions. Therefore, an anion exchange polymer is used to prepare a composite carbon as a CDI anode. Results from repetitive CDI testing shows that more efficient and consistent long-term salt removal is achieved when a flow-through CDI stack is configured with composite anodes compared to polymer-free anodes. Analysis of the effluent pH and steady-state current indicates that this performance improvement may be due to the minimization of parasitic reactions by shielding of the carbon electrodes with the selective polymer layer coated at the anode.