Engineering strategies toward electrodes stabilization in capacitive deionization

Capacitive deionization (CDI), an emerging desalination technique, harnesses porous carbon electrodes to eliminate ions via electrosorption. Despite its promise, CDI systems encounter persistent obstacles, chiefly the deterioration of carbon electrode efficiency over repetitive sorption/desorption cycles stemming largely from surface oxidation and corrosion. Herein, the review systematically investigates the pressing challenges impinging on electrode stability in CDI systems, including anodic oxidation reactions, cathodic reduction reactions, large volume changes, irreversible electrochemical reactions, and electrode fouling. Their detrimental impact on seawater desalination remains central. Diverging, it unpacks novel advances arising from diverse engineering strategies like surface, defect, interface, and structural engineering. Though nascent, these demonstrate immense potential to significantly strengthen CDI electrodes critical for water purification. In closing, the review evaluates scientific barriers and untapped opportunities around electrode stability, offering clear future outlooks for the expanding research area. It provokes consideration of questions whose answers could profoundly advance CDI technology. By broadly surveying the CDI landscape, the review seeks to catalyze rapid innovation in CDI electrode engineering.