Improvement of proton exchange membrane fuel cell performance in low-humidity conditions by adding hygroscopic agarose powder to the catalyst layer

A high-performance membrane electrode assembly (MEA) with agarose added to the anodic catalyst layer (CL) was successfully prepared. The MEA exhibited excellent performance at low relative humidity (RH) in an air/hydrogen proton exchange membrane fuel cell. The effects of agarose content, RH, cell temperature, and back pressure on the low-humidity performance of this MEA were investigated. The results of water contact angles and water uptake measurements reveal that the hydrophilicity of the anode is significantly improved with the addition of agarose. With a low RH of 20% and a cell temperature of 60 °C, the optimal MEA (MEA-4), containing 4 wt.% agarose in the anode CL, achieves excellent low-humidity performance: the current density reaches 960 mA cm−2 at 0.6 V and 500 mA cm−2 at 0.7 V. After 10 h of continuous operation under the same conditions, the current density decreases just slightly, from 960 to 840 mA cm−2, whereas the current density of a blank MEA without added agarose degrades sharply.