摘要
Hydrogen,especially the“green hydrogen”based on water electrolysis,is of great importance to build a sustainable society due to its high-energy-density,zero-carbon-emission features,and wide-range applications.Today's water electrolysis is usually carried out in either low-temperature(<100℃),e.g.,alkaline electrolyzer,or high-temperature(>700℃)applications,e.g.,solid oxide electrolyzer.However,the low-temperature devices usually suffer from high applied voltages(usually>1.5 V@0.01 A cm^(-2))and high cost;meanwhile,the high-temperature ones have an unsatisfied lifetime partially due to the incompatibility among components.Reasonably,an intermediate-temperature device,namely,proton ceramic cell(PCC),has been recently proposed.The widely-used air electrode for PCC is based on double O^(2-)/e^(-)conductor or composited O^(2-)/e^(-)-H^(+)conductor,limiting the accessible reaction region.Herein,we designed a single-phase La_(0.8)Sr_(0.2)Co_(1-x)Mn_(x)O_(3-δ)(LSCM)with triple H^(+)/O^(2-)/e^(-)conductivity as the air electrode for PCCs.Specifically,the La_(0.8)Sr_(0.2)Co_(0.8)Mn_(0.2)O_(3-δ)(LSCM8282)incorporates 5.8%proton carriers in molar fraction at 400℃,indicating superior proton conducting ability.Impressively,a high current density of 1580 mA cm^(-2) for hydrogen production(water electrolysis)is achieved at 1.3 V and 650℃,surpassing most low-and high-temperature devices reported so far.Meanwhile,such a PCC can also be operated under a reversible fuel cell mode,with a peak power density of 521 mW cm^(-2) at 650℃.By correlating the electrochemical performances with the hydrated proton concentration of single-phase triple conducting air electrodes in this work and our previous work,a principle for rational design of high-performance PCCs is proposed.
基金
This research was supported by Guangdong Postdoctoral Research Project(62104380),Guangdong Natural Science Funds for Distinguished Young Scholar.
