1D Magnetic Resonance Imaging, High Resolution 2D and Spin Counting Nuclear Magnetic Resonance for Batteries

In batteries and supercapacitors, the variation of lithium concentration profiles can be probed with <i>operando</i> 1D magnetic resonance imaging (MRI) of spin bearing atoms, while limiting the signal losses stemming from short relaxation times and broad lines in static systems. In such cases, one can observe interesting effects pertaining to the electrode porosity.[1] In model systems with materials displaying low diamagnetic susceptibilities, pulsed-field-gradient diffusion measurements shows the negative effect of carbon black addition on lithium ion self-diffusion.[2]<br/><br/>High-resolution Magic Angle Spinning NMR, on the other hand, can be performed on a wide variety of materials, and provide a wide range information on many atoms such as ⁷Li or ⁶Li, ²³Na and 2D correlation experiments can provide information on defects or phase separation in battery materials.[3]<br/><br/>Moreover, in favorable systems such as lithium titanates, it has been shown that surface fluorination with XeF₂ greatly improves the electrochemical properties. In such systems, high resolution MAS-NMR can help quantify the amount of fluorine in the structure, and the ¹⁹F chemical shift analysis yields information on the fluorine environment. Moreover, spin counting strategies based on HMQC experiments can provide the number of fluorine atoms which are coordinated to lithium ions and help understand what kind of structures are created locally upon fluorination.[4]<br/><br/><br/>[1] M.Tang, V.Sarou-Kanian, P.Melin, J.B.Leriche, M.Ménétrier, J.M.Tarascon, M.Deschamps, E.Salager, 'Following lithiation fronts in paramagnetic electrodes with in situ magnetic resonance spectroscopic imaging', <i>Nat. Commun.</i>, <b>7</b>, 13284 (2016)<br/><br/>[2] S.J.Tambio, M.Deschamps, V.Sarou-Kanian, A.Etiemble, T.Douillard, E.Maire, B.Lestriez, 'Self-Diffusion of Electrolyte Species in Model Battery Electrodes Using Magic Angle Spinning and Pulsed Field Gradient Nuclear Magnetic Resonance', <i>J. Power Sources</i>, <b>362</b>, 315-322 (2017)<br/><br/>[3] R.J.Messinger, M.Ménétrier, E.Salager, A.Boulineau, M.Duttine, D.Carlier, J.M.Ateba Mba, L.Croguennec, C.Masquelier, D.Massiot, M.Deschamps, 'Revealing Defects in Crystalline Lithium-Ion Battery Electrodes by Solid-State NMR: Applications to LiVPO₄F', <i>Chem. Mat.</i>, <b>27(15)</b>, 5212–5221 (2015)<br/><br/>[4] Y.Charles-Blin, D.Flahaut, J.B.Ledeuil, K.Guérin, M.Dubois, M.Deschamps, A.M.Perbost, L.Monconduit, H.Martinez, N.Louvain, 'Atomic Layer Fluorination of the Li₄Ti₅O₁₂ Surface: A Multiprobing Survey', <i>ACS Appl. Energy Mater.</i>,<b> 2(9)</b>, 6681-6692 (2019)