Robust Atomic-Resolution Imaging of Lithium in Battery Materials by Center-of-Mass Scanning Transmission Electron Microscopy

Abstract

The performance of energy storage materials is often governed by their structure at the atomic scale. Conventional electron microscopy can provide detailed information about materials at these length scales, but direct imaging of light elements such as lithium presents a challenge. While several recent techniques allow lithium columns to be distinguished, these typically either involve complex contrast mechanisms that make image interpretation difficult or require significant expertise to perform. Here, we demonstrate how center-of-mass scanning transmission electron microscopy (CoM-STEM) provides an enhanced ability for simultaneous imaging of lithium and heavier element columns in lithium ion conductors. Through a combination of experiments and multislice electron scattering calculations, we show that CoM-STEM is straightforward to perform and produces directly interpretable contrast for thin samples, while being more robust to variations in experimental parameters than previously demonstrated techniques. As a result, CoM-STEM is positioned to become a reliable and facile method for directly probing all elements within energy storage materials at the atomic scale.

Exploring the Nanoscale Origin of Performance Enhancement in Li1.1Ni0.35Mn0.55O2 Batteries Due to Chemical Doping

“…iDPC is a technique that maps the center‐of‐mass (COM) of the transmitted electron probe [ 33 ] and as such, is a linear contrast mechanism that can be used to simultaneously image both light and heavy elements in well‐oriented crystals, including Li in layered Mn oxide batteries. [ 34 ] Similar to LNMA10, both the M‐phase and R‐phase are readily identifiable in this image. However, in contrast, these phases are not present as nanodomains but, rather, are morphologically confined to the surface (R‐phase) and bulk (M‐phase).…”

In Situ and Emerging Transmission Electron Microscopy for Catalysis Research

“…In a recent paper published by Zachman et al, 4D-STEM imaging with advancements in data analysis was demonstrated to successfully image the atomic structure and interfacial charge transfer simultaneously for the first time. Moreover, the 4D-STEM technique can even be used to image light elements such as lithium atoms …”

“…Moreover, the 4D-STEM technique can even be used to image light elements such as lithium atoms. 307 With 4D-STEM, 306 one can capture ADF, BF, and CoM in tandem to uncover both structural and chemical information. In particular, the CoM of the electron beam intensity in the detector plane retains information on internal fields as it measures the momentum transfer from the specimen to the electron probe.…”

Atomic Resolution Cryogenic 4D-STEM Imaging via Robust Distortion Correction

“…By capturing most of the diffracted electrons on a pixelated detector, 4D-STEM allows for complex data analysis without physical hardware constraints. It offers the flexibility of reconstructing annular detector images in any arbitrary collection range and enables enhanced spatial resolution in both the lateral and depth directions via ptychographic reconstruction. , More importantly, 4D-STEM captures symmetry breaks within the sample and electron momentum transfer, which reveal important features such as charge distribution, ferroelectric polarization, magnetism, and the position of light elements without the need for specialized detectors. − This ability makes 4D-STEM an ideal technique to explore quantum materials, where the correlation between spin, charge, and lattice may cause exotic phenomena, which are otherwise difficult to characterize . However, most quantum phenomena occur at low temperatures, thus necessitating cryogenic cooling of the specimen.…”