Redesigning protonic ceramic electrochemical cells to lower the operating temperature.

Liu, Fan; Diercks, David; Kumar, Praveen; Seong, Arim; Jabbar, Mohammed Hussain Abdul; Gumeci, Cenk; Furuya, Yoshihisa; Dale, Nilesh et al. · Sci Adv · 2025

basic_science · Level V

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Abstract

Protonic ceramic electrochemical cells (PCECs) can operate at intermediate temperatures (450° to 600°C) for power generation and hydrogen production. However, the operating temperature is still too high to revolutionize ceramic electrochemical cell technology. Lowering the operating temperature to <450°C will enable a wider material choice and reduce system costs. We present approaches to redesigning PCECs via readily fabricated single-grain-thick, chemically homogeneous, and robust electrolytes and a nano-micro positive electrode. At 450°C, the PCECs achieve a peak power density of 1.6 watt per square centimeter on H<sub>2</sub> fuel, 0.5 watt per square centimeter on NH<sub>3</sub> fuel, and 0.3 watt per square centimeter on CH<sub>4</sub> fuel in fuel cell mode. In steam electrolysis mode, a current density of >0.6 ampere per square centimeter with a Faradaic efficiency of >90% is achievable at 1.4 volt and 400°C. In addition, exceptional durability (>2000 hours) has been demonstrated, with a degradation rate of <0.01 millivolt per 100 hours in fuel cell mode at 400°C.