Contribution to a book

FZJ-2023-04181

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png NAP-XPS Studies of Mixed Conducting Electrodes During High-Temperature Electrochemical Reactions

Müller, D. (Corresponding author)FZJ*

2023
WORLD SCIENTIFIC (EUROPE) London
ISBN: 978-1-80061-328-7 (print), 978-1-80061-329-4 (electronic)

Abstract: In this chapter, we will give an overview of how NAP-XPS can be used to investigate processes in and properties of mixed ionic electronic conducting materials at elevated temperatures, with a special focus on operando studies on working electrochemical devices. After a brief introduction of fundamental concepts of solid-state electroand defect chemistry, we will focus on the reactions of prototypical materials exposed to thermal, chemical, and electric stimuli and how those can be elucidated with NAP-XPS. After discussing the experimental challenges and general setups used, we use examples to showcase the capabilities of NAP-XPS. Starting with simple oxides, such as CeO2, where NAP-XPS is used to clarify mechanisms of electrocatalytic reactions with H2O and O2, we give several examples of how the technique was used to significantly improve the understanding of mixed conductors, the results themselves being used to further drive technique development. NAP-XPS shines brightly here, as surface-sensitive assessment of both electrostatic as well as chemical properties is unrivaled by any other technique. We extend the discussion to more complex multicomponent transition metal perovskites used in both cathodes and anodes of high-temperature electrochemical devices, here the element and chemical state sensitivity of NAP-XPS allows us to track atomic rearrangements on the surface induced by changes in electrochemical potentials, finishing with a short description of NAP-XPS experiments on cermets, a special case of a mixed conductor. This chapter is both intended for the solid-state (electro)chemist to showcase how NAP-XPS might help them to tackle physicochemical questions, as well as to introduce the basic concepts of solid-state ionics and electrochemistry to the spectroscopist, aiming to further the understanding between those two fields.

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Contributing Institute(s):

1. Elektronische Eigenschaften (PGI-6)

Research Program(s):

1. 632 - Materials – Quantum, Complex and Functional Materials (POF4-632) (POF4-632)
2. DFG project 319443528 - Magnetfeldunterstützte chemische Gasphasenabscheidung von Übergansmetalloxiden und in situ Untersuchungen der elektronischen Struktur mit Hilfe von Roentgenabsorptionsspektroskopie (MagSpec) (319443528) (319443528)

Appears in the scientific report 2023

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