Induced-Charge Assisted Faradaic Capacitive Deionization: A New Paradigm to Break the Capacity-Rate Trade-off

Faradaic capacitive deionization (Faradaic CDI) is a promising technology for tackling the global water crisis through efficient desalination. However, its practical implementation has been hindered by inherent challenges, such as sluggish reaction kinetics and limited mass transfer, especially under low-salinity conditions. To address these issues, this study proposes an induced-charge Faradaic CDI (IC-Faradaic CDI) system. The key innovation lies in the strategic integration of Faradaic CDI with an electric double-layer mechanism through a wireless induced-charge IC unit. This design modulates the electric field and ion transport, optimizes the concentration distribution, and establishes a universal pathway to reconcile the trade-off between kinetics and capacity. As a result, the IC-Faradaic CDI system delivers a desalination capacity of 0.269 mg cm^-2 and an outstanding average desalination rate of 0.027 mg cm^-2 min^-1, surpassing most existing Faradaic CDI systems. Furthermore, to validate its real-world applicability, a larger-scale system (324 cm²) was constructed, achieving 77% salt removal from simulated brackish water and the effective desalination of real brackish water from the Yangtze River estuary. This work provides a novel and universal strategy to alleviate the kinetic limitations of Faradaic CDI and offers a low-cost, membrane-free, and energy-efficient solution for high-performance water treatment.