Investigation of Dual Porous Transport Layers for High-Efficient and Durable Anion-Exchange Membrane Unitized Regenerative Fuel Cells

Abstract

Examination of the porous transport layer (PTL) in the oxygen electrode is important for anion-exchange membrane unitized regenerative fuel cells (AEM-URFC) where fuel cell (FC) and water electrolysis (WE) were operated in a single-cell. Here we report dual PTL incorporating two PTLs (carbon (C) and stainless steel (SUS)) to exhibit high performance under FC and WE modes. Ti-based PTL has been considered as PTL for URFC. However, C-based PTL has been widely used as PTL for anion-exchange membrane fuel cells and SUS-based PTL has been employed as PTL for anion-exchange membrane water electrolysis. When C- or SUS-based PTL was used as a single PTL, AEM-URFC exhibited low round-trip efficiency (RTE). To exhibit high round-trip efficiency (RTE), the investigation of PTL parameters and development of new PTL were conducted. As a result, the AEM-URFC with the dual PTL showed superior RTE and durability than that with the conventional Ti-based PTL. Also, it exhibited better cyclability compared to the that with conventional Ti-based PTL The Ni-foam PTL optimized in this study can be an efficient alternative to the conventional Ti-felt PTL because it can facilitate the enhanced AEMWE performance and durability.