4D Bragg Edge Tomography of Directional Ice Templated Graphite Electrodes

Area of Science:

• Materials Science
• Electrochemistry
• Neutron Imaging

Background:

• Lithium-ion batteries (LIBs) are crucial energy storage devices.
• Understanding electrode material behavior during cycling is key to improving LIB performance.
• Novel electrode architectures require advanced characterization techniques.

Purpose of the Study:

• To visualize the distribution of graphite and lithiation phases (LiC12, LiC6) in ultra-thick, directional graphite electrodes for LIBs.
• To investigate the crystallographic lithiation states and their correlation with the electrode state of charge using 4D neutron tomography.
• To assess the feasibility of applying 4D Bragg edge tomography to LIB electrodes.

Main Methods:

• Utilized four-dimensional (4D) Bragg edge wavelength-resolved neutron tomography.
• Performed tomographic imaging on novel, ultra-thick, directional ice-templated graphite electrodes.
• Mapped attenuation curves and Bragg edge parameters with ~300 µm spatial resolution.
• Correlated neutron tomography data with X-ray tomography data.

Main Results:

• Successfully visualized the distribution of graphite and stable lithiation phases (LiC12, LiC6) within the thick electrodes.
• Provided insight into crystallographic changes during de-/lithiation across the electrode thickness.
• Demonstrated the capability to map lithiation states in relation to the electrode's state of charge.
• Established the feasibility of 4D Bragg edge tomography for LIB electrode analysis.

Conclusions:

• 4D Bragg edge neutron tomography is a viable technique for characterizing complex LIB electrode structures.
• The method offers valuable insights into material transformations during battery operation.
• This study represents the first application of 4D Bragg edge tomography to LIB electrodes, opening new avenues for research.