Solid State Ionics

Solid-state ionics is the fundamental study of ion dynamics in solid materials. This is naturally of direct interest to us in the SEE group, as it is indeed moving ions that are the charge- and energy carriers in electrochemical storage systems. In this context, we are active in both the development of new ionic materials, as well as the fundamental understanding of ion-transport mechanisms in solid electrolytes and electrode materials. In order to probe ion conduction at multiple length- and time- scales, we utilize our unique set of expertise in ab initio simulations, nuclear magnetic resonance (NMR) spectroscopy and electrochemistry.

Recent highlights of the group’s work in this area include:

-Chuang Yu’s careful optimization of the ionic conductivity of Li6PS5Br published in the Journal of Materials Chemistry A 1–5. By carefully scanning key synthesis parameters such as annealing temperature or ball-milling speed we can tailor the structure of solid electrolytes and so control their key functional properties (ionic conductivity, electrochemical stability etc.).

-Swapna’s work on describing ion conduction across grain-boundaries in argyrodite solid electrolytes, published in ACS Energy Letters 6. By taking advantage of the different lithium NMR signal in the isostructural chlorine- and bromine-based argyrodite solid electrolytes we could perform exchange-NMR experiments to quantify the hopping of lithium across grains in the mixed powder sample which is typically very hard to do either experimentally or computationally.

-Niek’s code development to analyse molecular dynamics data published in ACS Applied Energy Materials  7–9. Using this collection of in-house-developed scripts we can obtain the atomistic diffusion path, the amplitude of vibrations, hopping rates, radial distribution functions and density distribution functions; all relevant metrics to our investigations of fundamental ion-conduction mechanisms in solids.

References

(1)         Yu, C.; Hageman, J.; Ganapathy, S.; van Eijck, L.; Zhang, L.; Adair, K. R.; Sun, X.; Wagemaker, M. Tailoring Li 6 PS 5 Br Ionic Conductivity and Understanding of Its Role in Cathode Mixtures for High Performance All-Solid-State Li–S Batteries. J. Mater. Chem. A 2019, 7 (17), 10412–10421. doi.org/10.1039/C9TA02126D.

(2)         Yu, C.; Ganapathy, S.; van Eck, E. R. H.; van Eijck, L.; de Klerk, N.; Kelder, E. M.; Wagemaker, M. Investigation of Li-Ion Transport in Li7P3S11 and Solid-State Lithium Batteries. J. Energy Chem. 2019, 38, 1–7. doi.org/10.1016/j.jechem.2018.12.017.

(3)         Yu, C.; Ganapathy, S.; Van Eck, E. R. H.; Van Eijck, L.; Basak, S.; Liu, Y.; Zhang, L.; Zandbergen, H. W.; Wagemaker, M. Revealing the Relation between the Structure, Li-Ion Conductivity and Solid-State Battery Performance of the Argyrodite Li6PS5Br Solid Electrolyte. J. Mater. Chem. A 2017, 5 (40), 21178–21188. doi.org/10.1039/c7ta05031c.

(4)         Yu, C.; Ganapathy, S.; Hageman, J.; Van Eijck, L.; Van Eck, E. R. H.; Zhang, L.; Schwietert, T.; Basak, S.; Kelder, E. M.; Wagemaker, M. Facile Synthesis toward the Optimal Structure-Conductivity Characteristics of the Argyrodite Li6PS5Cl Solid-State Electrolyte. ACS Appl. Mater. Interfaces 2018, 10 (39), 33296–33306. doi.org/10.1021/acsami.8b07476.

(5)         Yu, C.; Ganapathy, S.; de Klerk, N. J. J.; van Eck, E. R. H.; Wagemaker, M. Na-Ion Dynamics in Tetragonal and Cubic Na3PS4, a Na-Ion Conductor for Solid State Na-Ion Batteries. J. Mater. Chem. A 2016, 4 (39), 15095–15105. doi.org/10.1039/C6TA05896E.

(6)         Ganapathy, S.; Yu, C.; van Eck, E. R. H.; Wagemaker, M. Peeking across Grain Boundaries in a Solid-State Ionic Conductor. ACS Energy Lett. 2019, 4 (5), 1092–1097. doi.org/10.1021/acsenergylett.9b00610.

(7)         de Klerk, N. J. J.; van der Maas, E.; Wagemaker, M. Analysis of Diffusion in Solid-State Electrolytes through MD Simulations, Improvement of the Li-Ion Conductivity in β-Li 3 PS 4 as an Example. ACS Appl. Energy Mater. 2018, 1 (7), 3230–3242. doi.org/10.1021/acsaem.8b00457.

(8)         De Klerk, N. J. J.; Wagemaker, M. Diffusion Mechanism of the Sodium-Ion Solid Electrolyte Na3PS4 and Potential Improvements of Halogen Doping. Chem. Mater. 2016, 28 (9), 3122–3130. doi.org/10.1021/acs.chemmater.6b00698.

(9)         De Klerk, N. J. J.; Rosłoń, I.; Wagemaker, M. Diffusion Mechanism of Li Argyrodite Solid Electrolytes for Li-Ion Batteries and Prediction of Optimized Halogen Doping: The Effect of Li Vacancies, Halogens, and Halogen Disorder. Chem. Mater. 2016, 28 (21), 7955–7963. doi.org/10.1021/acs.chemmater.6b03630.