posted on 2024-01-25, 12:33authored byKeun-Hwan Oh, Heejin Kim, Kwan Woo Nam
One of the key components of the fuel cell stack is a
metallic
bipolar plate (MBP) that plays multiple roles, such as current collector,
fuel and oxidant distributor, and mechanical support. However, corrosion
and consequent metal elution are major drawbacks of the MBP because
they diminish the efficiency and power performance of membrane-electrode
assemblies (MEAs). Herein, we show that the crown ether (CE) additive
can simultaneously inhibit surface corrosion of the MBP and act as
a scavenger for eluted metal ions to alleviate contamination of other
components. From the electrochemical measurement, high-resolution
imaging, and elemental analysis, we have found that the CE undergoes
electrolytic decomposition and makes an efficient protective layer
in an in situ manner. This layer prevents direct contact between the
MBP and electrolyte as well as the dissolution of metal ions into
the electrolyte. In addition, we demonstrate that the CE can improve
the recovery protocol of the MEA owing to the formation of host–guest
complexes between the CE and metal cations. These results provide
key insights into the design of high-performance MBPs for proton-exchange
membrane fuel cells.