Batch fabrication of micro-tubular protonic ceramic fuel cells via a phase inversion-based co-spinning/co-sintering technique

Abstract

Micro-tubular protonic ceramic fuel cells (MT-PCFCs) are prominently advantageous in energy conversion and storage, such as intermediate operating temperature, large volumetric power density, and low sealing requirements. Formation of thin and dense electrolyte film and efficient current collection, particularly from the micro lumen, are the primary challenges for preparing high-performance MT-PCFCs. The present work carries out a one-step fabrication of triple-layer hollow fibers (TLHFs) with anodic current collector/graded anode/electrolyte using BaCe0·7Zr0·1Y0·2O3-δ via the phase-inversion based co-spinning/co-sintering technique. A BaCo0·4Fe0·4Zr0·1Y0·1O3-δ based porous cathode is then applied on the TLHF's outer surface to create a complete fuel cell. The resultant single MT-PCFC yields a peak power density of 601.2 mW cm−2 at 700 °C. Furthermore, an MT-PCFC stack is made by bundling seven TLHFs using the porous cathode. With an effective area exceeding 12 cm2, the MT-PCFC stack generates a power output of 2.5 W at 700 °C. The stability test lasts for 100 h at 600 °C under 100 mA cm−2 and for next 60 h at varied temperatures from 700 to 600 °C under 200 mA cm−2. The inventive design of TLHFs facilitates the scale-up of fuel cells, promoting the development of a large-scale MT-PCFC stack or systems.