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

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)×10–2 S cm–1 at 95 oC and 98% relative humidity, benefited from the spiral H3O+/H2O chains in the 1D pore channels studded with COOH/COO– groups.