Functional layer engineering to improve performance of protonic ceramic fuel cells
Ning Wang, Zhiyin Huang, Chunmei Tang, Lixin Xing, Ling Meng, Yoshitaka Aoki, Lei Du, Siyu Ye
Abstract
Abstract Protonic ceramic fuel cells (PCFCs) have been attracting increasing attention because of their advances in high‐efficiency power generation in an intermediate‐temperature range, as compared to the high‐temperature solid oxide fuel cells (SOFCs). The greatest difference between PCFCs and SOFCs is the specific requirement of protonic (H + ) conductivity at the PCFC cathode, in addition to the electronic (e − ) and oxide‐ion (O 2− ) conductivity. The development of a triple H + /e − /O 2− conductor for PCFC cathode is still challenging. Thus, the most‐widely used cathode material is based on the mature e − /O 2− conductor. However, this leads to insufficient triple phase boundary (TPB), i.e., reaction area. Herein, an efficient strategy that uses a ~ 100 nm‐thick proton conductive functional layer (La 0.5 Sr 0.5 CoO 3− δ , LSC55) in‐between the typical La 0.8 Sr 0.2 CoO 3− δ cathode (a mature e − /O 2− conductor, LSC82) and BaZr 0.4 Ce 0.4 Y 0.1 Yb 0.1 O 3− δ electrolyte (11 mm in diameter, 20 μm in thickness) is proposed to significantly enhance the reaction area. Reasonably, the ohmic resistance and polarization resistance are both decreased by 47% and 62%, respectively, compared with that of PCFCs without the functional layer. The power density of the PCFC with such a functional layer can be raised by up to 2.24 times, superior to those described in previous reports. The enhanced PCFC performances are attributed to the well‐built TPB and enhanced reaction area via the functional layer engineering strategy.