Editors’ Choice—4D Neutron and X-ray Tomography Studies of High Energy Density Primary Batteries: Part I. Dynamic Studies of LiSOCl2 during Discharge

Ralf F Ziesche,Matthew D R Kok,Winfried Kockelmann,Nikolay Kardjilov,James B Robinson,Henning Markötter,Paul R Shearing,Ingo Manke,Dan J L Brett

doi:10.1149/1945-7111/abbbbc

Abstract

The understanding of dynamic processes in Li-metal batteries is an important consideration to enable the full capacity of cells to be utilised. These processes, however, are generally not directly observable using X-ray techniques due to the low attenuation of Li; and are challenging to visualise using neutron imaging due to the low temporal resolution of the technique. In this work, complementary X-ray and neutron imaging are combined to track the dynamics of Li within a primary Li/SOCl2 cell. The temporal challenges posed by neutron imaging are overcome using the golden ratio imaging method which enables the identification of Li diffusion in operando. This combination of techniques has enabled an improved understanding of the processes which limit rate performance in Li/SOCl2 cells and may be applied beyond this chemistry to other Li-metal cells.

Highlights

Lithium batteries have transformed energy storage technology due to their significantAc common cell chemistries for such applications is the Li metal vs. thionyl chloride (SOCl2) [4–7] cell which is suitable for applications under extreme conditions including very low or https://mc04.manuscriptcentral.com/jes-ecs high temperatures [8,9]
Where X-rays are more sensitive to metallic cell components such as the battery casing or the current collectors, neutrons visualise inter alia the lithium diffusion
The combination of both techniques helps to understand processes which are hidden for one technique or localise battery components, such as the cathode current collector in the cell centre, which are invisible for neutrons but the location is important for the analysis

Summary

Introduction

Lithium batteries have transformed energy storage technology due to their significant. In contrast to most us reactor based neutron sources, neutron spallation sources such as the ISIS neutron source at the Rutherford Appleton Laboratory (UK) have a lower time-averaged neutron flux which makes imaging of dynamic processes with the conventional scanning strategies more difficult To overcome this challenge, methods such as the Golden Ratio (GR) strategy can be employed. The total discharging process took about h, after which the cell had delivered a capacity of 832 mAh. After correcting each projection using the dark and open beam images, and after filtering white spots, 3D reconstructions were performed via the FBP algorithm for a parallel beam using the ASTRA us cri pt pte https://mc04.manuscriptcentral.com/jes-ecs toolbox [48,49] reconstruction library within the python programming language. Before starting the 3D reconstruction, the projections were corrected by the dark field and open beam images which were collected before and after the scan and binned by a factor of two to reduce the reconstruction time and data size resulting in a reconstructed pixel size of 40.4 μm

Results and Discussion

Conclusions

Methods