Advantageous of Hybrid Fuel Cell Operation under Self-Humidification for Energy Efficient Bipolar Membrane

Because of a unique sandwiched structure of proton and anion exchange membranes, the bipolar membrane (BPM) enables self-humidification at their junction in fuel cell operation. In this work, a novel BPM was prepared from the sulfonated poly(ether ether sulfone) (SPEES) acidic and the quaternized polysulfone (QPS) alkaline membranes via layer-by-layer process. A variety of advantageous membrane and electrochemical properties associated with its self-humidification were investigated under the membrane electrode assembly operation at steady-state with generation of water molecules at the interface even at low humidity. The proton and hydroxide ion conductivity of the membranes used in this BPM were quite high-0.053 S cm(-1) for SPEES and 0.014 S cm(-1) for QPS, respectively. The H-2/O-2 single fuel cell test with this BPM showed the power density up to 75 mW cm(-2) at 100% relative humidity (RH) and 67 mW cm(-2) at 0% RH, while that with the corresponding proton exchange membrane prepared from single SPEES showed lower power density at 0% RH with the collapse of the membrane by burning.