Approaching high temperature performance for proton exchange membrane fuel cells with 3D ordered silica/Cs2.5H0.5PW electrolytes

Abstract

Development of new types of proton conducting materials with efficient transport of protons is one of the most important remaining challenges for elevated-temperature proton exchange membrane fuel cells. Herein, we report the design and synthesis of a new type of proton conducting material based on three dimensional ordered macroporous silica (3DOM silica) incorporated with inorganic Cs_2.5H_0.5PW electrolytes. The highly ordered structure of 3DOM silica provides well inter-connected pathways for efficient proton transport, especially at high operating temperatures. At a doping amount of 90 wt% of Cs_2.5H_0.5PW, the proton conductivity of the formed composite electrolyte reaches 0.248 S cm⁻¹ at 170 °C and the activation energy is about 5.775 kJ mol⁻¹. The novel electrolytes also showed good stability as well as excellent single cell performance at 170 °C. The results described here demonstrate that the 3DOM silica/Cs_2.5H_0.5PW electrode has great potential for high temperature proton exchange membrane fuel cell applications.