Structure Engineering-Driven Symmetrical Double-Sided Electrolyte Design for Fabricating Ultra-Flat Planar Protonic Ceramic Electrochemical Cells

Abstract

Protonic ceramic electrochemical cells (PCECs) are highly efficient devices for producing hydrogen through steam electrolysis or generating electricity from hydrogen or hydrocarbon fuels. However, scaling up PCECs has been challenging due to the significant shrinkage mismatch between the thin electrolyte layer and the thick NiO-electrolyte composite hydrogen electrode support layer. These issues cause stress accumulation and cell bending, adversely affecting cell performance. To overcome this challenge, a structure engineering-driven symmetric double-sided electrolyte (DE) design is presented to mitigate asymmetrically distributed thermal stresses during cell sintering. The resulting 1-inch DE cells have an ultra-flat surface with a thickness variation of less than 0.1 mm and show enhanced electrochemical performance with improved thermal cycling tolerance, with a lower OCV degradation rate of 9.5 mV/100 h over 80 cycles. Additionally, this design has been successfully validated with larger size 5×5 cm2 PCECs. This structural design marks a significant advancement in planar PCECs fabrication, offering a promising approach for large scale manufacturing.

Keywords: PCECs, Symmetric structure, Double-sided electrolyte, Electrochemical performance, Shrinkage mismatch, Thermal cycling stability