Highly Efficient and Durable Materials for Protonic Ceramic Electrochemical Cells Operated at 400~600 ○c

Abstract

Protonic ceramic electrochemical cells (PCECs) is an emerging and attractive approach to store intermittent renewable energies which can be converted back to electricity in reversible operation, aiming to achieve the energy conversion and storage in an electrochemical manner. Economically competitive PCEC systems have distinct advantages over conventional oxygen-ion conducting counterpart (O-SOC), but further materials innovation is still needed to improve unit-cell performance and durability at reduced operating temperature (400~600○C), enhance system lifetime and reduce cost. To achieve efficient electrochemical hydrogen and power production with stable operation, highly robust and durable oxygen electrode is urgently desired to facilitate water oxidation and oxygen reduction reactions simultaneously, which are the critical technical barriers for both electrolysis and fuel cell operation at reduced temperatures. The recent efforts have been focused on developing new triple conducting electrode with perovskite perovskite structure for high-performance and stable PCECs. The systematic material characterizations are carried out to evaluate the feasibility of activity, stability and interface compatibility, such as Fourier-transform infrared spectroscopy, high-temperature X-ray diffraction, hydrogen permeation and first-principal computation. The catalytic activity towards electrochemical reactions is demonstrated in various electrochemical performance evaluations at 400~600○C. The long-term durability of the PCEC is examined to show the high resistance against transient current density change in reversible operation and high steam concentration.