Abstract
Non-flammable and high-temperature stable ionic liquid (IL)-based electrolytes could eliminate catastrophic battery failures and improve battery safety, but their poor electrochemical interaction with the LiNixMnyCozO2 (NMC) family of cathodes is a long-standing problem due to severe parasitic reactions at high temperature. Understanding surface and bulk structural mechanisms of NMC-type cathodes at elevated operational temperature is of paramount importance to facilitate stable electrochemical performance. Here, we report a non-flammable phosphonium IL-based cell chemistry that offers stable electrode-electrolyte interfaces, leading to electrochemical performance up to 125°C and high-temperature safety. We combine electrochemistry with multimodal X-ray spectroscopy methods to understand interfaces at elevated temperature (100°C). This nanoscale understating enables a proof-of-concept high-temperature cylindrical cell (14500), and the design achieves an average Coulombic efficiency of ≈99.5% up to 300 cycles at 100°C. The results ascertain the significance of depth-dependent degradation at the interface, guiding room-temperature Li-ion technology toward extreme-temperature applications.
| Original language | English |
|---|---|
| Article number | 102597 |
| Journal | Cell Reports Physical Science |
| Volume | 6 |
| Issue number | 5 |
| DOIs | |
| State | Published - May 21 2025 |
| Externally published | Yes |
Funding
This material is based upon work supported by the National Science Foundation (NSF) under NSF award numbers 1751472 and 2127519 . We also acknowledge funding support from the Advanced Energy Consortium (AEC) ( BEG14-02 ). http://www.beg.utexas.edu/aec/partners companies include BHP, Shell, ExxonMobil, US Department of Energy (DOE), Repsol, Sandia National labs, and Total Energies. This research used resources of the National Synchrotron Light Source II (NSLS-II), a US DOE Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under contract DE-SC0012704. NEXAFS and HAXPES measurements were performed at the National Institute of Standards and Technology (NIST) beamlines SST-1 and SST-2, respectively in the NSLS-II. This research also used resources of the Center for Functional Nanomaterials, which is a US DOE Office of Science Facility at Brookhaven National Laboratory under contract no. DE-SC0012704. This research used resources of the Advanced Photon Source (APS), an Office of Science User Facility operated for the US DOE Office of Science by Argonne National Laboratory under contract no. DE-AC02-06CH11357. We acknowledge the Lumigen Instrument Center at Wayne State University for the use of its XRD (NSF: MRI 1427926) facility. S.N. acknowledges The Electrochemical Society (United States) for the 2022 F.M. Becket Summer Fellowship. Special thanks are extended to Research Experience for Undergraduates (REU) Dayana Flores (California Polytechnique) and Nicole Traynor (University of South Florida) for their assistance during electrochemical sample preparations.
Keywords
- Li-ion batteries
- X-ray absorption spectroscopy
- cathode electrolyte interphase
- electrode-electrolyte interface
- environmental safety
- high-temperature batteries
- ionic liquid electrolytes
- non-flammability