Directional Ion Transport Through Nanoarchitected 1D Mesochannels: 2D Polymer Interfacial Engineering for High‐Efficiency Capacitive Deionization

Abstract The development of high‐performance capacitive deionization (CDI) electrodes demands innovative materials that integrate rapid ion transport, high salt adsorption capacity (SAC), and oxidative stability. This challenge is addressed through a surface nanoarchitectonics strategy, constructing 2D mesochannel polypyrrole/reduced graphene oxide heterostructures (mPPy/rGO) with ordered 1D mesochannels (~8 nm) parallel to the graphene surface. By confining the self‐assembly of cylindrical polymer brushes on freestanding rGO substrates, directional ion highways are simultaneously engineered that significantly reduce transport tortuosity. In addition, corrosion‐resistant polymer interfaces block oxygen penetration, and strong interfacial interactions between PPy and rGO ensure efficient electron transfer. The mPPy/rGO‐based CDI cell achieves breakthrough performance: ultrahigh SAC of 84.1 mg g −1 (4.5× activated carbon, the salt concentration: 2 g L −1 ), and 96.8% capacity retention over 100 cycles in air‐equilibrated saline solution (the salt concentration: 500 mg L −1 ). This interfacial confinement methodology establishes a universal paradigm for designing polymer‐based desalination materials with atomically precise transport pathways.