Siebenhofer Matthäus, Nenning Andreas, Rameshan Christoph, Blaha Peter, Fleig Jürgen, Kubicek Markus
Institute of Chemical Technologies and Analytics, TU Wien, Vienna, Austria.
Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
Nat Commun. 2024 Feb 26;15(1):1730. doi: 10.1038/s41467-024-45824-9.
Improving materials for energy conversion and storage devices is deeply connected with an optimization of their surfaces and surface modification is a promising strategy on the way to enhance modern energy technologies. This study shows that surface modification with ultra-thin oxide layers allows for a systematic tailoring of the surface dipole and the work function of mixed ionic and electronic conducting oxides, and it introduces the ionic potential of surface cations as a readily accessible descriptor for these effects. The combination of X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) illustrates that basic oxides with a lower ionic potential than the host material induce a positive surface charge and reduce the work function of the host material and vice versa. As a proof of concept that this strategy is widely applicable to tailor surface properties, we examined the effect of ultra-thin decoration layers on the oxygen exchange kinetics of pristine mixed conducting oxide thin films in very clean conditions by means of in-situ impedance spectroscopy during pulsed laser deposition (i-PLD). The study shows that basic decorations with a reduced surface work function lead to a substantial acceleration of the oxygen exchange on the surfaces of diverse materials.
改进用于能量转换和存储设备的材料与优化其表面密切相关，而表面改性是提升现代能源技术的一种很有前景的策略。本研究表明，用超薄氧化层进行表面改性能够系统地调整混合离子电子导体氧化物的表面偶极子和功函数，并引入表面阳离子的离子势作为这些效应的一个易于获取的描述符。X射线光电子能谱（XPS）和密度泛函理论（DFT）相结合表明，离子势低于主体材料的碱性氧化物会诱导正表面电荷并降低主体材料的功函数，反之亦然。作为该策略广泛适用于定制表面性质的概念验证，我们在脉冲激光沉积（i-PLD）过程中通过原位阻抗谱，在非常洁净的条件下研究了超薄装饰层对原始混合导电氧化物薄膜氧交换动力学的影响。研究表明，表面功函数降低的碱性装饰会使多种材料表面的氧交换显著加速。
