钙钛矿氧化物是很有前景的氧还原(ORR)、氧析出(OER)电催化材料，但其低电导率是面向应用必须克服的壁垒。钙钛矿中存在氧离子、电子以及混合导电多种行为，目前尚未阐明不同导电机制与本征催化活性的关联，使获得高电导率的催化剂缺乏理论设计依据。为此，本项目选取具有氧离子、电子和混合电导行为的代表性体系作为研究对象，通过掺杂和热处理引入不同程度的氧空位来调控电导行为。通过碱性条件下的电化学测试揭示氧空位对ORR、OER过电势的影响规律；利用交流阻抗谱结合有限元模拟，以及施加小直流偏压研究有无直流电场下材料的导电机理、真实电导率以及材料/电极界面的电荷转移。通过以上研究探索ORR、OER本征活性与总电导率、电子电导率与离子电导率之间的关系，建立电导行为与催化活性的关联性模型。本项目的顺利开展，不仅能根据宏观电导行为对催化活性进行有效预测，更为有针对性的提高电导率而进行缺陷化学设计提供依据。

Perovskite-type oxides are promising electrocatalysts towards oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The low electrical conductivity is one of the major barriers for their catalytic performances. Perovskites can present complex electrical behaviors such as oxide-ion conduction, electronic conduction and mixed ionic-electronic conduction. Lack of correlative description between the electrical conduction behavior with the intrinsic catalytic activity obstructs the materials design to obtain electrocatalysts with high conductivity. This project aims to solve the above problem by carrying out systematic investigations on three series of perovskite-type oxides showing representative electrical conduction behaviors. Different levels of oxygen vacancy will be introduced to the materials either by chemical doping or by various heat treatment conditions to tune the electrical conduction behaviors. Electrochemical analysis in alkaline media will be carried out to establish the relationship between ORR、OER overpotential and oxygen vacancy. Impedance spectroscopy under various pO2 will be employed to reveal the conduction mechanism, and finite element modeling is used to obtain the real electrical conductivity of the catalyst powder from porous pellets. A small dc bias will be also applied to investigate the defect chemistry and the charge transfer at the material/electrode interface. Through the above investigations to explore the relationship between the ORR、OER overpotential and the total conductivity, electronic conductivity and oxide-ion conductivity, and establish the correlative model between electrical conduction behavior and the catalytic activity. Completion of this project will not only establish a macro descriptor to explain or predict the electrocatalytic activity, but also benefit the defect chemistry design to enhance the electrical conductivity of perovskite-type electrocatalysts.