In honor of the 80th anniversary of the discovery of EPR, Applied Magnetic Resonance has put together a special issue "EPR at 80" (https://lnkd.in/gnBJ27zx).
Together with Adrienne Delluva and Kevin Finch, we wrote a review for this special issue related to the magnetics of lithium ion batteries. A view-only version is available from the publisher here (https://rdcu.be/dSb6W ).
The review highlights measurements of Lithium-ion battery materials by SQUID magnetometry, EPR and NMR, and reflects on the magnetic nature of cathode materials used in LiB. The review of these lab scale measurements provides the context for our work at TDA Research showing that full scale commercial LiB have a magnetic field signature which can be interpreted in terms of battery state of health.
At TDA Research, we are building new measurement tools based on this observation, but also want to understand the "why". To that end we propose a very rough initial model that could reflect the EPR, NMR and SQUID magnetic measurements, as well as our own operando in-field magnetometry measurements. The model is incomplete, but it is intended to spur discussion in the wider magnetics and battery communities. The fully developed magnetics model of batteries will one day have to explain phenomena from the scale of atoms all they way up to battery modules in an electric vehicle.
Understanding LiB from a magnetics perspective is equally as important as understanding them from an electrochemical one. The magnetic nature of LiB cathode materials sits upon a foundation of the dynamic, 3D arrangement of the interacting magnetic moments of "billions and billions" of unpaired electrons. Even at 80 years on, we still have only begun to scratch the surface of what we can understand using EPR alone. We also increasingly see the power of its application as part of a suite of magnetic resonance and magnetics measurement tools for materials analysis.
