A Mechanically Robust, Extreme Environment-Stable, and Fast Ion Transport Nanofluidic Fiber.

Constructing mechanically strong and environmentally stable nanofluidic fibers with excellent ion transport remains a challenge. Herein, we design a mechanically robust and stable aramid nanofiber/carboxylated aramid nanofiber (ANF/cANF) hybrid nanofluidic fiber with a high ionic conductivity via a wet spinning-induced orientation strategy. Benefiting from the oriented structure and strong interfacial interactions of the filaments, the ANF/cANF nanofluidic fiber exhibits a high tensile strength of 276.8 MPa. Carboxylation and oriented nanochannels dramatically reduce the charge transfer resistance, resulting in a high ionic conductivity. As a result, the ANF/cANF nanofluidic fiber obtains a 5-fold increase in ionic conductivity compared to that of the disordered fiber. Notably, the nanofluidic fiber maintains its structural integrity and mechanical properties after 90 days of immersion in water. Additionally, it retains its favorable surface-charge-dominated ion transport capabilities even under extreme conditions, including exposure to acids, alkalis, and ethanol, as well as after treatments at high (150 °C) and low (-196 °C) temperatures.