Interfacial Coordination Engineering of Phthalocyanine‐Based cMOF/LDH Heterostructures for Superior Capacitive Deionization

Abstract

Capacitive deionization (CDI) faces critical challenges, primarily due to conventional electrodes suffering from limited adsorption capacity, sluggish kinetics, and poor cycling stability. To simultaneously overcome these issues, this study introduces a novel coordination stabilized CoPc‐NiO4/LDH composite electrode, designed through a combined experimental and theoretical approach. Specifically, the strong coordination interaction between the conductive metal–organic framework CoPc‐NiO4 and NiCo‐LDH creates a stable interfacial coordination structure, which dramatically shortens the ion diffusion path and accelerates charge transfer via robust Ni─O─C coordination bonds. As a result, the novel structural configuration greatly enhances the stability of the electrode and facilitates faster ion removal kinetics. It delivers an impressive adsorption capacity of 134.7 mg g−1, the average desalination rate of 15.3 mg g−1 min−1, a notable charge efficiency of 92%, and maintains excellent cycling durability, retaining 94.7% of its capacity after 100 operational cycles. Density functional theory (DFT) calculations substantiate the experimental findings by demonstrating atomic‐level electron redistribution at the interface, clarifying the strong binding energy (‐1.85 eV) of Ni─O─C bonds, which effectively suppresses structural distortions. Overall, this work reveals the critical role of interfacial coordination chemistry in regulating charge storage and structural durability, guiding the rational design of high‐performance CDI materials.