Capacitive deionization (CDI) technology, as an emerging method for water treatment and resource recovery, has made significant progress in recent years. Its unique electro-adsorption mechanism demonstrates great potential in seawater desalination, wastewater treatment, and resource recovery. The energy efficiency of CDI technology is crucial to its application potential. High energy efficiency not only reduces operating costs but also improves the overall performance and sustainability of the system. This directly affects the competitiveness of CDI technology, making it essential to optimize its energy efficiency.

This paper reviews recent advancements in enhancing the energy efficiency of CDI technology, summarizing and synthesizing aspects of energy optimization, management, and recovery. This includes optimizing electrode materials, improving device design, and refining operating modes to reduce system resistance and leakage current. Direct energy recovery is achieved by connecting charged and uncharged CDI units, while indirect energy recovery is realized by storing energy from the discharge process in energy storage devices such as supercapacitors.

In the future, as research on energy optimization, management, and recovery in CDI technology continues to deepen, it will include the development of electrode materials with higher conductivity and the design of intelligent energy management systems to achieve optimal energy utilization and recovery. The application potential of CDI technology in water treatment and resource recovery will become broader and more efficient.