A semiconductor-based electrolyte in a ceramic fuel cell (SCFC) has the potential to improve the device performance even at lower temperatures (≤520 °C) mainly due to its high ionic conductivity. Here, we present a chemically stable perovskite semiconductor Nb-doped SrTiO_3−δ (STN) electrolyte for the SCFC, which reached a high power density of 678 mW/cm² and a high open-circuit voltage (OCV) of 1.03 V at 520 °C. The STN showed a high ionic conductivity of 0.22 S/cm. Electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), and band structure analysis revealed that the high ionic conductivity is due to an increase in oxygen vacancies and band gap modulation. It was also found that the bending of the energy band at the electrode/electrolyte interface helps to block the electrons and thus avoids the problem of short circuit. These results indicate that doping and energy band gap modulation can be effective approaches to develop advanced semiconductor electrolytes for SCFCs.

中文翻译：

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半导体Nb掺杂SrTiO3 _-δ钙钛矿型陶瓷燃料电池电解质

陶瓷燃料电池（SCFC）中基于半导体的电解质即使在较低的温度（≤520°C）下也具有改善设备性能的潜力，这主要归因于其高离子电导率。在这里，我们介绍了一种用于SCFC的化学稳定的钙钛矿半导体掺Nb的SrTiO3 _-δ（STN）电解质，其功率密度达到678 mW / cm ²520°C时的开路电压（OCV）为1.03V。STN显示出0.22 S / cm的高离子电导率。电化学阻抗谱（EIS），X射线光电子能谱（XPS）和能带结构分析表明，高离子电导率是由于氧空位和带隙调制的增加所致。还发现电极/电解质界面处的能带的弯曲有助于阻挡电子，因此避免了短路问题。这些结果表明，掺杂和能带隙调制可以是开发用于SCFC的先进半导体电解质的有效方法。