Dual-Dimensional Interwoven Proton Exchange Membrane Exhibiting High Anhydrous Proton Conductivity Around Room Temperature

Abstract

Developing proton exchange membranes (PEMs) that operate efficiently around room temperature and anhydrous conditions remains a critical challenge in electrochemical devices. Conventional linear polymers typically suffer from poor confinement of strong acids and ill-defined proton conduction pathways, which limit their practical applications. Herein, we report an anhydrous proton exchange membrane (MSA@CTF-AP), which is constructed by confining a strong acid (methanesulfonic acid, MSA) within a polymeric network that consists of three-dimensional (3D) triazine frameworks interwoven with one-dimensional (1D) polymer segments. In this hybrid architecture, the rigid 3D domains provide more stable proton conduction pathways, while flexible 1D polymer segments maintain the mechanical integrity of membrane. As a result, the membrane exhibits a high anhydrous proton conductivity exceeding 10^–3 S cm^–1 around room temperature, along with excellent long-term cycling stability, retaining over 99% of its initial capacity after 7500 cycles in proton battery systems. Compared to liquid and powder-based proton electrolytes, this continuous self-standing membrane displays enhanced structural and performance stability, making it a promising proton electrolyte candidate for next-generation proton batteries and other related nonaqueous electrochemical devices operating around room temperature.