Tian Hanchen, Li Wenyuan, Ma Liang, Yang Tao, Guan Bo, Shi Wangying, Kalapos Thomas L, Liu Xingbo
Mechanical & Aerospace Engineering Department, Benjamin M. Statler College of Engineering & Mineral Resources, West Virginia University, Morgantown, West Virginia 26506, United States.
School of Materials Science and Engineering, Hebei University of Engineering, Handan 056038, China.
ACS Appl Mater Interfaces. 2020 Nov 4;12(44):49574-49585. doi: 10.1021/acsami.0c12987. Epub 2020 Oct 20.
Triple-conducting materials have been proved to improve the performance of popular protonic ceramic electrolysis cells. However, partially because of the complexity of the water-splitting reaction involving three charge carriers, that is, oxygen (O), proton (H), and electron (e), the triple-conducting reaction mechanism was not clear, and the reaction conducting pathways have seldom been addressed. In this study, the triple-conducting Ruddlesden-Popper phase PrBaNiO as an anode on the BaCeZrYYbO electrolyte was fabricated and its electroresponses were characterized by electrochemical impedance spectroscopy with various atmospheres and temperatures. The impedance spectra are deconvoluted by means of the distribution of the relaxation time method. The surface exchange rate and chemical diffusivity of H and O are characterized by electrical conductivity relaxation. The physical locations of electrochemical processes are also identified by atomic layer deposition with a surface inhibitor. A microkinetics model is proposed toward conductivities, triple-conducting pathways, reactant dependency, surface exchange and bulk diffusion capabilities, and other relevant properties. Finally, the rate-limiting steps and suggestions for further improvement of electrode performance are presented.
三传导材料已被证明可提高流行的质子陶瓷电解槽的性能。然而，部分由于涉及三种电荷载流子（即氧（O）、质子（H）和电子（e））的水分解反应的复杂性，三传导反应机理尚不清楚，且反应传导途径很少被探讨。在本研究中，制备了作为BaCeZrYYbO电解质上阳极的三传导Ruddlesden-Popper相PrBaNiO，并通过在不同气氛和温度下的电化学阻抗谱对其电响应进行了表征。阻抗谱通过弛豫时间分布方法进行反褶积。通过电导率弛豫表征H和O的表面交换速率和化学扩散率。还通过使用表面抑制剂的原子层沉积确定了电化学过程的物理位置。针对电导率、三传导途径、反应物依赖性、表面交换和体扩散能力以及其他相关性质，提出了一个微观动力学模型。最后，给出了速率限制步骤以及进一步提高电极性能的建议。
