A breakthrough hydrogen and oxygen utilization in a H2-O2 PEMFC stack with dead-ended anode and cathode

Abstract

Proton exchange membrane fuel cells (PEMFCs) have been wildly used for marine and aerospace applications as energy devices, where pure hydrogen and oxygen are fed into the two sides of the membrane electrode assembly (MEA). The release of unreacted hydrogen and oxygen not only reduces the efficiency of the system but also causes the serious problem of hydrogen starvation. For this reason, fuel flow driving devices and methods such as pumps, ejectors, and solenoid valves are designed to recycle this unused gas. However, even with these devices, the release of gas into the environment is still inevitable. Therefore, this paper introduces a novel method that solves these problems and mitigates gas emissions using a dead-ended anode and cathode (DEAC) system. Pressure difference is formed between the inlet and outlet of PEMFC by controlling the purge valve to remove water and recycle hydrogen during purging. The dynamic response characteristics of this system under different current densities, pressure differences, and purging intervals are experimentally investigated in detail. The results show that both the hydrogen and oxygen utilizations can reach 100% and the collection of generated water during gas purging can be achieved in the DEAC mode.