Grant: Research Tools and Instruments

The electrolyte of a lithium-ion cell is analogous to the blood in an animal. As the electrolyte degrades, the cell will begin to fail. Monitoring the composition of the electrolyte and the changes to the electrolyte during charge-discharge cycling of the cell allows one to learn about cell failure mechanisms and then correct them. This akin to blood tests used to diagnose illnesses and diseases in humans. Our laboratory heavily uses NMR spectroscopy to monitor changes in battery electrolyte. This is presently done at the Dalhousie NMR facility where large NMR spectrometers that use expensive and rare liquid helium and employed. ******This request is for a benchtop NMR spectrometer which uses a permanent magnet and therefore no liquid helium. Modern benchtop NMR spectrometers are simple and inexpensive to use, highly robust and can be powered from a 115V outlet. The time needed to collect a high quality spectrum is also extremely short, on the order of a few minutes. ******Our laboratory creates over 1000 Li-ion and “anode-free” pouch-type cells per month for a variety of tests. Many of these cells are subjected to NMR analysis of their electrolyte after testing, and an even larger fraction should be. The results of the experiments are highly valuable and the number of students in my lab using this technique is now six and is growing rapidly. Access to the Dalhousie NMR facility is proving to be insufficient and inconvenient. A benchtop NMR system will allow us to increase our productivity and hence increase our ability to create high energy density lithium batteries with longer lifetime. Our recent success has been highlighted in the media, for example: https://marker.medium.com/tesla-may-have-invented-a-million-mile-electric-car-battery-c3c11cc76d84 ******Benchtop NMR spectrometers can normally be set to be able to measure three nuclei and we will select H, Li and F. H is a component in all the non-aqueous solvents that are used in the electrolyte. Li is, of course, present in the electrolyte as the salt. We and others have shown that the Li salt content decreases in Li-ion cells under certain conditions during charge and discharge cycling. Finally, F is a component of the LiPF6 salt and of useful electrolyte additives such as fluoroethylene carbonate and LiPO2F2. These can be tracked during cell aging by NMR.******The Dahn lab is a diverse and inclusive environment of about 25 researchers. Over 33% of the personnel are female and over 40% are racially visible minorities. Graduate students and postdocs are from all over the world, including Canada, USA, China, Tunisia, Egypt and Estonia. A visiting graduate student from Thailand will join in January of 2020. **