Redesigning protonic ceramic electrochemical cells to lower the operating temperature
Fan Liu, David R. Diercks, Praveen Kumar, Arim Seong, Mohammed Hussain Abdul Jabbar, Cenk Gümeci, Yoshihisa Furuya, Nilesh Dale, Takanori Oku, Masahiro Usuda, Pejman Kazempoor, Iman Ghamarian, Lin Liu, Liyang Fang, Di Chen, Zixian Wang, Stephen J. Skinner, Chuancheng Duan
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 2 fuel, 0.5 watt per square centimeter on NH 3 fuel, and 0.3 watt per square centimeter on CH 4 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.