Open framework-based Brønsted acid-Lewis base interfaces boost proton transfer in the fuel cells.

Limited proton conductivity within the catalyst layer induces severe ohmic polarizations and constrains power output at high hydrogen-to-electricity efficiencies in proton exchange membrane fuel cells. We demonstrate that proton transfer can be boosted by constructing Brønsted acid-Lewis base interfaces through integrating organic open frameworks with Nafion. These confined interfaces mediate low-barrier relay pathways, disrupt hydrogen bonding to expedite water network reorganization, facilitate consecutive proton transfer, and enrich protons locally. Compared with Nafion, the complexes exhibit an order-of-magnitude increase in proton self-diffusion coefficient, a 6.5-fold rise in proton conductivity, and a 55% reduction in activation energy. When integrated with commercial platinum on carbon, they deliver a fourfold increase in rated power output relative to the baseline, outperforming representative state-of-the-art membrane electrode assemblies with advanced catalysts under similar conditions.