In Situ Electron Diffraction Tomography Using a Liquid-Electrochemical Transmission Electron Microscopy Cell for Crystal Structure Determination of Cathode Materials for Li-Ion batteries

Abstract

We demonstrate that changes in the unit cell structure of lithium battery cathode materials during electrochemical cycling in liquid electrolyte can be determined for particles of just a few hundred nanometers in size using in situ transmission electron microscopy (TEM). The atomic coordinates, site occupancies (including lithium occupancy), and cell parameters of the materials can all be reliably quantified. This was achieved using electron diffraction tomography (EDT) in a sealed electrochemical cell with conventional liquid electrolyte (LP30) and LiFePO crystals, which have a well-documented charged structure to use as reference. In situ EDT in a liquid environment cell provides a viable alternative to in situ X-ray and neutron diffraction experiments due to the more local character of TEM, allowing for single crystal diffraction data to be obtained from multiphased powder samples and from submicrometer- to nanometer-sized particles. EDT is the first in situ TEM technique to provide information at the unit cell level in the liquid environment of a commercial TEM electrochemical cell. Its application to a wide range of electrochemical experiments in liquid environment cells and diverse types of crystalline materials can be envisaged.

Automated electron diffraction tomography – development and applications

“…samples such as metal-organic frameworks (MOFs) (Denysenko et al, 2011;Rhauderwiek et al, 2018;Wang et al, 2018), small organic molecules (Gorelik et al, 2012) such as pigments (Teteruk et al, 2014) or pharmaceuticals (van Genderen et al, 2016;Wang et al, 2017;Palatinus et al, 2017;Das et al, 2018;Gruene et al, 2018;Jones et al, 2018) as well as proteins (Nederlof et al, 2013;Lanza et al, 2019). Furthermore, the method was proven to be even suitable for in situ investigations (Karakulina et al, 2018). The crystal sizes shown here in these examples are in the regime of several hundred down to one hundred nanometres.…”

Serial protein crystallography in an electron microscope

“…Augmenting parallel-beam crystallography with coherent scanning diffraction techniques such as convergent-beam diffraction or low-dose ptychography might be a viable way to obtain Bragg reflection phase information 51,52 . Finally, integrating the serial acquisition approach with emerging methods of in situ and time-resolved EM [53][54][55] may open up avenues for roomtemperature structures or structural dynamics studies on beamsensitive systems. All of this makes STEM-based SerialED a versatile, highly efficient and low-cost alternative to canonical structure determination approaches for proteins and beyond.…”

Serial protein crystallography in an electron microscope

“…Augmenting parallel-beam crystallography with coherent scanning diffraction techniques such as coherent nano-area diffraction, convergent-beam diffraction or low-dose ptychography might be a viable way to obtain Bragg reflection phase information 51,52 . Finally, integrating the serial acquisition approach with emerging methods of in-situ and time-resolved electron microscopy 53,54 may open up avenues for structural dynamics studies on beam-sensitive systems. All of this makes STEM-based serial electron diffraction a versatile, highly efficient and low-cost alternative to canonical structure determination approaches for proteins and beyond.…”