Exploring Interfaces in Li-ion All-Solid-State Batteries
Solid State and Surface Chemistry, Material Synthesis
Synthesis and Properties of Functional Materials
Final Report Abstract
The necessary transition towards renewable energy resources requires the development of safe, reliable, and cost-efficient energy storage systems. However, the dominating commercial lithium batteries are usually based on liquid electrolytes (media that transports lithium ions during charge and discharge) that are flammable and/or toxic. One promising alternative to the current standard are solid electrolytes (SEs), the use of which would result in All-Solid- State Batteries (ASSBs). Unlike their liquid counterparts, SEs do not pose the same flammability and toxicity risks. To date, only little is known about the chemical mechanisms that underpin parameters such as Li-ion transport in solid electrolytes, the structures and compositions formed both in the active materials and their interfaces during synthesis and operation, and how the microscopic properties of the starting materials influence the electrochemical performance. In this research project, we investigated the interfacial stability of a new promising, fast charging anode material towards state-of-the-art SEs and were able to identify one stable candidate that could lead to a functioning ASSB. We could trace the decomposition products of other SEs by a combined X-Ray, solid-state NMR, and electron microscopy approach. These finding allow a more directed synthesis of new stable electrolytes and active materials. In addition, we explored the effect of dopants on the local structure of one of the most promising SE. Very pure and crystalline samples allowed us to investigate the local structure of this SE with unprecedented resolution by solid-state NMR, which allowed us to quantify the occupation and thus the local distribution of dopants and charge carriers. Thereby, we could proof Li ion trapping in the vicinity of the dopants. Finally, we were able to synthesize a completely new class of highly conductive SEs that are inherently stable towards lithium metal. We investigated the structure and Li ion dynamics of these metastable electrolytes by solid state NMR, NMR relaxometry and PXRD.
Publications
- Unravelling the reaction mechanism of SiO anodes for Li-ion batteries by combining in situ 7Li and ex situ 7Li/29Si solid-state NMR spectroscopy. J. Am. Chem. Soc. 2019, 141, 7014−7027
K. Kitada, O. Pecher, P. C. M. M. Magusin, M. F. Groh, R. S. Weatherup, and C. P. Grey
(See online at https://doi.org/10.1021/jacs.9b01589) - Doped Li7La3Zr2O12 (LLZO) Garnets as Li-ion Solid-State Battery Electrolytes: Atomistic Insights into Local Coordination Environments and their Influence on NMR Spectra, J. Am. Chem. Soc. 2020
B. Karasulu, S. P. Emge, M. F. Groh, C. P. Grey, A. J. Morris
(See online at https://doi.org/10.1021/jacs.9b12685)
