Enhanced salt removal performance of flow electrode capacitive deionization with high cell operational potential

[Display omitted] •Flow electrode capacitive deionization operated in the range 1.2 to 4.5 V.•Salt removal efficiency and removal rate increase with higher operational potential difference.•No noticeable electrode reactions or water electrolysis were observed up to 2.5 V. Capacitive deionization (CDI) is an emerging technology with great potential to be energy efficient and allow cost-effective operation for the removal of salt ions from saline water. The introduction of flow electrode to CDI greatly enhanced the salt removal performance at much higher salt concentration, even at seawater level, due to not needing a discharging process, which is required for conventional CDI desalination. Since the oxidation of carbon electrodes and water electrolysis leads to the decrease in desalination performance and long-term stability of the CDI cell, it has typically been operated at the potential difference