A hot tip: imaging phenomena using in situ multi-stimulus probes at high temperatures

Abstract

Accurate high temperature characterization of materials remains a critical challenge to the continued advancement of various important energy, nuclear, electronic, and aerospace applications. Future experimental studies must assist these communities to progress past empiricism and derive deliberate, predictable designs of material classes functioning within active, extreme environments. Successful realization of systems ranging from fuel cells and batteries to electromechanical nanogenerators and turbines requires a dynamic understanding of the excitation, surface-mediated, and charge transfer phenomena which occur at heterophase interfaces (i.e. vapor-solid, liquid-solid, solid-solid) and impact overall performance. Advancing these frontiers therefore necessitates in situ (operando) characterization methods capable of resolving, both spatially and functionally, the coherence between these complex, collective excitations, and their respective response dynamics, through studies within the operating regime. This review highlights recent developments in scanning probe microscopy in performing in situ imaging at high elevated temperatures. The influence of and evolution from vacuum-based electron and tunneling microscopy are briefly summarized and discussed. The scope includes the use of high temperature imaging to directly observe critical phase transition, electronic, and electrochemical behavior under dynamic temperature settings, thus providing key physical parameters. Finally, both challenges and directions in combined instrumentation are proposed and discussed towards the end.

Toward Electrochemical Studies on the Nanometer and Atomic Scales: Progress, Challenges, and Opportunities

“…Other systems have also been explored. 150,151 One of the most important challenges in studying charge transport in electrochemical systems is the need to separate the electronic current from the ionic one with high spatial resolution. While the common amperometric techniques such as electrochemical impedance spectroscopy (EIS) suffer from low spatial resolution, KPFM and EFM, having highresolution, are sensitive to both electronic and ionic processes and only detect the overall charge distribution.…”

“…Figure d–l shows topographic and CPD maps and CPD profiles in the cathode, solid electrolyte, and anode of the SOFC. ,, These data allowed the estimation of the ion transport activation barrier for the SOFC materials. Other systems have also been explored. , …”

Probing vacancy behavior across complex oxide heterointerfaces

“…Scanning surface potential microscopy (SSPM) is a modified two-pass local probe technique used to determine the surface potential of material surfaces with nanoscale precision (27), thus yielding highly localized physical and electrochemical properties. High temperatures present significant hurdles for local probe studies of energy-related material systems, where in situ SSPM under operating conditions, or so-called operando measurements, has only been recently introduced (28,29). We previously used SSPM to characterize interfacial potential perturbations, active zone widths, and triple-phase boundary widths of solid oxide fuel cell electrode/electrolyte assemblies and CeO 2 -based solid oxide electrolysis cell electrodes at intermediate operation temperatures (T = 500°to 600°C) with a customized miniature environmental chamber (30)(31)(32)(33).…”

High temperature conductance mapping for correlation of electrical properties with micron-sized chemical and microstructural features

“…have been reported [3]. The majority of literature on SPM concerns measurements at temperatures below ~200 °C and measurements at higher temperatures combined with a controlled atmosphere at atmospheric pressure are very limited, as recently reviewed by Nonnenmann [4]. With the CAHT-SPM we have developed a technique based on AC conductance measurements using a lock-in amplifier.…”