Enhanced proton conduction of crystalline organic salt hybrid membranes and the performance of fuel cells

Abstract

Among the components of a proton exchange membrane fuel cell (PEMFC), the proton exchange membrane (PEM) is an essential constituent part of the fuel cell. Here, a crystalline organic salt (HCOS-1) with amino and sulfonate groups has been synthesized. HCOS-1 exhibited a high proton conductivity of 3.23 × 10⁻³ S cm⁻¹ at 100 °C and 93% relative humidity (RH). In order to improve its proton conductivity, HCOS-1 was blended with Nafion to prepare a composite membrane. At 100 °C and 98% RH, the composite membrane containing 6 wt% HCOS-1 exhibits a higher proton conductivity of 7.24 × 10⁻³ S cm⁻¹, which is more than twice compared with 3.35 × 10⁻³ S cm⁻¹ of the recast Nafion membrane. Compared with the recast Nafion membrane, the maximum power density of the hydrogen–oxygen fuel cell using the 6 wt% HCOS-1 composite membrane at 80 °C and 100% RH has increased by 9.95%, from 815 mW cm⁻² to 896 mW cm⁻².