Tactics for boosting the desalination stability of capacitive deionization

Abstract

Capacitive deionization (CDI), as a burgeoning desalination technology, has gained significant attention due to its merit of simple operation, low cost, environmental friendliness, and ion selectivity. Despite advancements in the theoretical framework of CDI and the emergence of novel electrode materials, the persistent challenge of poor cycling stability remains a major obstacle, hindering the further development of CDI. Notably, improving the cycling stability of carbon-based CDI and faradic CDI (FDI) by optimizing CDI cells, operation modes and electrode materials holds great significance for realizing its commercial application. Herein, this review provides an overview of studies related to the desalination stability of carbon-based CDI and FDI. The research status of both carbon materials and faradic materials is comprehensively summarized, specifically on analyzing various side reactions that occur during long-term operation, the corresponding solutions are systematically outlined to improve desalination stability of carbon-based CDI and FDI, including operational condition optimizing, ion exchange membrane introducing, nitrogen doping, surface coating, yolk-shell confinement and “inside out” growth. The review further compares the efficacy of these tactics on boosting the desalination stability and finally expounds the development prospect of CDI for practical application.