Superhigh intrinsic proton conductivity in densely carboxylic covalent organic framework

Herein, we developed for the first time two carboxylic acid based intrinsic proton conductors (COOH-COF-1 and COOH-COF-2) via pre-assembly approach. The obtained COOH-COF-1 and COOH-COF-2 not only show outstanding chemical and thermal stabilities, but also exhibit superhigh intrinsic proton conductive behaviors. Especially, the intrinsic proton conductivity of COOH-COF-2 is up to 2.6 × 10−3 S/cm at 353 K and 98% RH, which is the highest value among all the reported acid functionalized COFs. This work lights up the way for the rational design of functional COFs with remarkably intrinsic proton conducting performance and related practical applications.