Work

Carbon-based electrode materials for sustainable capacitive deionization: Energy efficiency, performance metrics, and scalability challenges

Year: 2026

Type: article

Abstract: Growing freshwater scarcity, rapid industrialization, population growth, and climate change have intensified the demand for sustainable and energy-efficient desalination technologies. Among emerging electrochemical water-treatment approaches, capacitive deionization (CDI) and flow-electrode capacitive deionization (FCDI) have attracted significant attention because of their low operating voltage, modular design, operational flexibility, and potential for resource recovery. Despite substantial progress, a comprehensive understanding of how electrode materials, charge-storage mechanisms, system configurations, and operational parameters collectively influence desalination performance and scalability remains fragmented across the literature. This review critically examines the development of CDI and FCDI technologies, with particular emphasis on carbon-based electrode materials and their role in electrochemical desalination. The fundamental mechanisms governing ion removal, including electric double-layer formation, co-ion effects, and Faradaic charge storage, are discussed alongside the evolution of major CDI architectures, such as membrane CDI, inverted CDI, hybrid CDI, desalination batteries, and FCDI. Recent advances in carbon-based electrodes, flow-electrode materials, membrane integration, reactor design, and process optimization are systematically evaluated in relation to desalination efficiency, ion selectivity, energy consumption, and operational stability. Emerging applications in wastewater treatment, selective ion separation, nutrient recovery, and resource recovery are also highlighted. Current challenges associated with electrode degradation, membrane fouling, flow-electrode conductivity, process standardization, scale-up, and commercialization are critically discussed. Finally, future research directions involving advanced material design, intelligent process optimization, renewable-energy integration, and hybrid treatment systems are identified to support the practical deployment of CDI and FCDI technologies for sustainable water treatment and resource management.

Source: Green Energy and Resources

DOI: 10.1016/j.gerr.2026.100204

Authors: Robel Ahmed, S.M Saklain Mostak Saumik, Md Rasel Ahmed, Md Yeanur Rahman, Md Abdullah Al Shahil, Monjur Mourshed

Institutions: Rajshahi University of Engineering and Technology, Hajee Mohammad Danesh Science and Technology University

Language: English

Topic: Membrane-based Ion Separation Techniques

Subfield: Biomedical Engineering

Field: Engineering

Domain: Physical Sciences

SDGs: Clean water and sanitation, Affordable and clean energy, Climate action

Open Access status: gold

Estimated APC paid: $1,500