SOLID-STATE NMR CHARACTERIZATION OF BATTERY MATERIALS

In this presentation, some of the recent solid state NMR results obtained in our laboratory in the research of new and advanced battery materials will be briefly reviewed. Examples will be shown that include sodium and lithium-based cathodes, anodes and solid electrolytes (polymeric, ceramic and composites). It will be shown how these solid-state NMR results were used to obtain crucial information about the structure and the dynamics in these materials, as well as in the identification of degradation products and the structural and dynamic changes taking place during electrochemical cycling. We will also show that the observations made by solid state NMR were successfully used to understand and predict the performance of many of these materials. In particular, the covered topics will include:
• Cathodes:
We will illustrate how paramagnetic solid-state NMR can be successfully implemented using a combination of fast MAS (>50 kHz) and low field magnets (200 MHz), allowing the accurate analysis of even very strong paramagnetic cathode materials. In particular, the topics presented will illustrate how this technique was applied in our laboratory to the characterization of: ion dynamics1, dopants2,3, structural defects4, cathode decomposition5 and the presence of irreversible phases6.
• Anodes:
The solid-state NMR analysis of Li containing alloys will be briefly described. It will be illustrated how the Knight shifts governing the NMR spectra of metals can be used in the structural and dynamic analysis of these compounds and how solid-state NMR can accurately detect the presence of Li dendrites7.
• Solid electrolytes:
The NMR research carried out in several ultrafast ceramic ionic conductors will be briefly presented.8,9 In these cases, solid state NMR was used in the structural characterization of the solid materials and to understand and follow the mechanism of material degradation. These results were used to design processes that significantly improved the Li+ conductivity. Solid state NMR was also used to detect the Li+ exchange process between the ceramic and polymer phases in a solid composite material10.
References:
1 E Gonzalo, M Zarrabeitia, N Drewett, J M López del Amo, T Rojo Energy Storage Materials 2021, 34, 682-707
2 L Yang, J M López del Amo, Z Shadike, S Bak, F Bonilla, M Galceran, P Kumar Nayak, J Buchheim, X Yang, T Rojo, P Adelhelm Advanced Functional Materials 2020, 30 (42), 2003364
3 L Yang, L‐Y Kuo, J M López del Amo, P Kumar Nayak, K A M