(Invited) Ambient Pressure XPS: Revealing Elemental, Chemical, and Potential Information across a Wide Range of Electrochemical Systems

Abstract

Interfaces play an important role in nearly all aspects of life, and are essential for electrochemistry. Electrochemical systems ranging from high temperature solid oxide fuel cells (SOFC) to batteries to capacitors have a wide range of important interfaces between solids, liquids, and gases which play a pivotal role in how energy is stored, transferred, and/or converted. The ability to study these interfaces has proven to be difficult and is only further exacerbated by the limited number of techniques capable of operating under in situ/operando environments. To overcome these challenges, we use in situ/operando ambient pressure X-ray Photoelectron Spectroscopy (APXPS). APXPS is a photon-in/electron-out process that can provide both atomic concentration and chemical specific information at pressures greater then 20 Torr. Using synchrotron X-rays at Lawrence Berkeley Nation Laboratory, the Advanced Light Source has several beamlines dedicated to APXPS endstations that are outfitted with various in situ/operando features such as heating to temperatures > 500 °C, pressures greater then 20 Torr to support solid/liquid experiments and electrical leads to support applying electrical potentials supports the ability to collect XPS data of actual electrochemical devices while its operating in near ambient pressures. This talk will introduce this technique and provide several solid/gas and solid/liquid interface electrochemistry examples using operando APXPS including solid-state Li-air batteries, magnesium metal anode surface chemistry, and the ability to probe the electrochemical double layer (EDL). Gaining new insight to guide the design and control of future electrochemical interfaces.