A deep dive into cell breating
In our new publication in Advanced Materials Interfaces we were able to quantify how much of the cell breathing in a solid-state battery cell came from the cathode and anode, respectively, just by measuring the three-electrode open-circuit potential at different pressures. No need for any advanced in situ techniques like XRD or dilatometry!
The key was to use a zero-strain reference electrode based on partially reduced LTO, which enables you to determine the molar reaction volume of the anode and cathode lithiation reactions separately.
We hope that this simple method will be useful to the community, and that it will further our understanding of cell breathing in solid-state batteries!
In the Graphite | LPSCl | NMC model system explored in this paper, we found that most of the pressure increase during the charge could be attributed to graphite, but that the continued graphite expansion was counteracted by NMC shrinking towards the end of charge (blue shaded area in the figure above), leading to the pressure levelling out.
In collaboration with HIU
A big thanks to our co-authors at HIU: Mervyn Soans, Dominic Bresser, and Alberto Varzi. This work was performed within the project REFA (Referenz-Elektroden für Festkörper-Akkumulatoren, 03EI6055) financed by the Federal Ministry for Economic Affairs and Energy.
The publication is part of the special collection “Microstructures and Interfaces in Solid-State Batteries” in Advanced Materials Interfaces and ChemElectroChem. You can find the open source publication here:
Using a Zero-Strain Reference Electrode to Distinguish Anode and Cathode Volume Changes in a Solid-State Battery
Do you want to use this method?
This method for separating the cell breathing into the anode and cathode contributions was made possible by the three-electrode configuration of the CompreCell DP, and the whole procedure could be completely automated using the CompreDrive. Check out the full description of the method in the paper.