Single-crystal superprotonic conductivity in an interpenetrated hydrogen-bonded quadruplex framework.

A proton-transporting pathway is crucial to the conduction mechanism in fuel cells and biological systems. Here, we report a novel 5-fold interpenetrated three-dimensional (3D) hydrogen-bonded quadruplex framework, which exhibits an ultrahigh single-crystal proton conductivity of 1.2(1) × 10 S cm at 95 °C and 98% relative humidity, benefitting from the spiral HO/HO chains in 1D pore channels studded with COOH/COO groups.