Solid State NMR Techniques for the Study of Structure/Property Correlations in Glassy and Glass Ceramic Materials for Energy Storage Applications

FAPESP 2013-07793-6 and 2017-17800-0)

High energy storage materials such as lithium and sodium ion batteries require fast solid electrolytes to maintain high current densities. Recently attention has been shifted from lithium to sodium owing to the latter’s much higher natural abundance and more widespread geographical distribution. The project focuses on characterizing the structural and dynamical features of superionic glass-ceramic electrolyte systems suitable for all-solid state sodium ion batteries. These systems, which crystallize in the hexagonal Na-Super Ion Conductor (NASICON) structure, are derived from the phase MTi2(PO4)3 (M = Li, Na). Ionic conductivities can be improved iso- and aliovalent substitution and glass ceramic processing. Modern high-resolution solid state NMR techniques are being used for the structural analysis of glasses and ceramics and for studying the mechanistic details of the crystallization process. In addition, we characterize the local ion dynamics of the sodium ions by temperature dependent NMR lineshape and multidimensional correlation functions, in concert with electrical conductivity measurements. Using these approaches we are studying the effect of cation substitution in the NASICON framework structure, of both network former and alkaline ion mixing on the cation sites and their effect on ion transport properties.

NASICON Structure and identification of the local environments
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Publications

Glass-to-crystal transition in the NASICON glass-ceramic system Na1+xAlxM2−x(PO4)3 (M=Ge, Ti)
H. Bradtmüller, A. M. Nieto-Munoz, J. F Ortiz-Mosquera, A.C.M. Rodrigues, H. Eckert, J. Non-Cryst. Solids 489, 91-101 (2018).

Preparation, Structural Characterization and Electrical Conductivities of Highly Ion-Conducting Glasses and Glass Ceramics in the System Li1+xAlxSnyGe2−(x+y)(PO4)3, S. H. Santagneli, H. V. A. Baldacim, S. J. L. Ribeiro, S. Kundu, A. C. M. Rodrigues, C. Doerenkamp, H. Eckert. J. Phys. Chem. C 120, 14556-14567 (2016).

Glass-to-Crystal Transition in Li1+xAlxGe2-x(PO4)3:, Structural Aspects Studied by Solid State NMR, C. Schröder, J. Ren, A. C. M. Rodrigues, H. Eckert, J. Phys. Chem. 118, 9400-9411 (2014).