Engineering Prussian Blue and Analogues for Sustainable Capacitive Deionization from Laboratory Development to Industrial Deployment

Abstract

Water scarcity and salinity pose acute challenges to sustainable development, requiring efficient, scalable and environmentally responsible water treatment technologies. Capacitive deionization (CDI) is emerging as a highly sustainable and energy-efficient water purification technology with notable advantages for brackish water desalination, wastewater treatment, and decentralized small-scale systems. The development of scalable and high-performance electrode materials are critical to accelerate and its transition toward industrial and commercial adoption. Prussian Blue (PB) and Prussian Blue analogues (PBAs), with their open-framework crystalline structures, rapid and reversible ion-storage capabilities, and high theoretical capacitance, have recently gained attention as next-generation CDI electrode materials. Despite promising laboratory-scale results, key challenges including long-term electrode stability, large-scale synthesis, environmental compatibility, and reliable performance under real-water conditions remain unresolved. This review provides a comprehensive assessment of recent advances in PB and PBA design, synthesis, and CDI performance, with a particular focus on their feasibility for industrial-scale manufacturing and deployment. Strategies such as multi-metallic analogues, hierarchical porous architectures, and hybrid composites with conductive materials are examined to enhance desalination capacity, rate capability, and operational durability. Furthermore, critical barriers to commercialization are discussed, including scalable and cost-effective synthesis, integration into modular pilot-scale systems, and performance in complex water matrices. Finally, this review offers techno-economic perspectives and practical insights to guide the development and industrial translation of PB-based CDI technologies, advancing sustainable and affordable clean-water solutions.