High single Zn-ion conductive porous organic conductors decorated with dense acidic groups via double post-synthetic sulfonations

Solid Zn-ionic conductors are one of the important components of rechargeable aqueous Zn-ion batteries. Although ion-conductive porous materials have been intensively studied due to their effective conduction pathways through large surface areas and tunable functionalities, porous material-based Zn ion conductors have been rarely reported because the strong electrostatic bonding properties of divalent Zn²⁺ ions generally lead to slow diffusion rates and low conductivity. Herein, we prepared porous organic polymer (POP)-based Zn-ion conductors via multiple post-synthetic modifications. The porous conductor with a large number of Zn-ion-incorporated sites exhibited a conductivity value of 3.24×10⁻⁴ S cm⁻¹, and a transference number of 0.94, which are the highest values among other porous materials. The long-term performance of conductivity was retained for at least one week. This work highlights the remarkable effectiveness of multiple post-synthetic modifications to achieve high Zn-ion conductivity and provides the first demonstration of a Zn-ion POP conductor.