Elaborate Designed Three-Dimensional Hierarchical Conductive MOF/LDH/CF Nanoarchitectures for Superior Capacitive Deionization.

Rational exploration of cost-effective, durable, and high-performance electrode materials is imperative for advancing the progress of capacitive deionization (CDI). The integration of multicomponent layered double hydroxides (LDHs) with conjugated conductive metal-organic frameworks (c-MOFs) to fabricate bifunctional heterostructure electrode materials is considered a promising strategy. Herein, the fabrication of hierarchical conductive MOF/LDH/CF nanoarchitectures (M-CAT/LDH/CF) as CDI anodes via a controllable grafted-growth strategy is reported. In this assembly, carbon fiber (CF) provides exceptional electrical conductivity facilitating rapid ion transfer and acts as a sturdy foundation for even distribution of NiCoCu-LDH nanosheets. Moreover, the well-ordered NiCoCu-LDH further acts as interior templates to create an interface by embedding c-MOFs and aligning two crystal lattice systems, facilitating the graft growth of c-MOFs/LDH heterostructures along the LDH nanosheet arrays on CF, leading to accelerated ion diffusion kinetics. Density functional theory (DFT) confirms enhanced interfacial charge transfer between NiCoCu-LDH and M-CAT, leading to improved ion transfer and smoother Cl- shuttle. Accordingly, the asymmetrical M-CAT/LDH/CF cell exhibits superior specific capacitance, salt adsorption capacity, rapid rate, and cyclic stability. This work offers valuable insights for designing heterostructure electrode materials based on three-dimensional interconnected networks, contributing to further advancements in CDI technology.