Research Area

All-solid-state batteries (ASSB) offer high energy density and are a safer alternative to conventional liquid-electrolyte-based Li-ion batteries. However, electrolyte selection is limited, and those exhibiting competitive ionic conductivities often exhibit high interfacial impedance. Thin film batteries are ASSBs with thickness of only a few micrometers, which have the benefits of solid-state batteries with the potential to be incorporated in microelectronics. Further, they provide with ideal platforms for interfacial studies due to their well-defined geometries. Thin film subgroup in LESC has been exploring new thin film battery compositions and their interfaces, along which novel characterization techniques, including cryogenic focused ion beam (cryo-FIB), cryogenic scanning/transmission electron microscopy (cryo-S/TEM), solid-state nuclear magnetic resonance (ss-NMR) and neutron depth profiling (NDP), etc. have been incorporated to facilitate the interfacial study of air-/beam-sensitive battery materials.

Recently, we have demonstrated the structural and chemical evolution across the interphase between Li metal and LiPON via cryo S/TEM, which provides valuable insights for interface engineering to further improve the interfacial stability. Another work successfully resolved the structure of amorphous LiPON by ss-NMR coupled with DFT calculation, where LiPON is shown to be a low-connectivity glass, influencing its mechanical properties and its stability with Li metal. Future work of thin film subgroup will continue the study on the cathode/solid electrolyte interface along with developing cryogenic in situ methodologies for probing dynamic changes at the beam-sensitive interfaces and in phase-change materials.

Highlighted Publications:

1. D. Cheng, T. A. Wynn, X. Wang, S. Wang, M. Zhang, R. Shimizu, S. Bai, H. Nguyen, C. Fang, M. Kim, W. Li, B. Lu, S. J. Kim and Y. S. Meng, “Unveiling the Stable Nature of the Solid Electrolyte Interphase between Lithium Metal and LiPON via Cryogenic Electron Microscopy“, Joule, 2020, 4, 11, 2484-2500

2. M. A. T. Marple, T. A. Wynn, D. Cheng, R. Shimizu, H. E. Mason, and Y. S. Meng, “Local structure of glassy lithium phosphorus oxynitride thin films: a combined experimental and ab initio approach“, Angew. Chem. Int. Ed. 2020, 59, 2–11

3. J. Z. Lee, T. A. Wynn, M. A. Schroeder, J. Alvarado, X. Wang, K. Xu, and Y. S. Meng, “Cryogenic Focused Ion Beam Characterization of Lithium Metal Anodes“ ACS Energy Letters, 2019, 4, 489

4. J. Z. Lee, T. A. Wynn, Y. S. Meng, D. Santhanagopalan, “Focused Ion Beam Fabrication of LiPON-based Solid-state Lithium-ion Nanobatteries for In Situ Testing” . J. Vis. Exp, 2018, e56259

5. J. Z. Lee, Z. Wang, H. L. Xinb, T. A. Wynn, and Y. S. Meng, “Amorphous Lithium Lanthanum Titanate for Solid-State Microbatteries“, Journal of The Electrochemical Society, 2017, 164(1), 6268

6. Z. Wang, D. Santhanagopalan, W. Zhang, F. Wang, H. L. Xin, K. He, J. Li, N. Dudney, and Y. S. Meng,”In Situ STEM-EELS Observation of Nanoscale Interfacial Phenomena in All-Solid-State Batteries“, Nano Letters,   2016, 16 (6), 3760