The Pore Size (IMAGE) Moscow Institute of Physics and Technology Caption The pore size is directly related to the efficiency of the fuel cell. The selective permeability of these pores, which resemble the aperture of a camera, determines how efficiently ions are screened, and consequently how efficiently energy is converted in a fuel cell. Credit Image courtesy of the authors of the study. Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.