Abstract
Solvent-mediated routes have emerged as an effective, scalable, and low-temperature method to fabricate sulfide-based solid-state electrolytes. However, tuning the synthesis conditions to optimize the electrolyte’s morphology, structure, and electrochemical properties is still underexplored. Here, we report a new class of composite solid electrolytes (SEs) containing amorphous Li3PS4 synthesized in situ with a poly(ethylene oxide) (PEO) binder using a one-pot, solvent-mediated route. The solvent and thermal processing conditions have a dramatic impact on the Li3PS4 structure. Conducting the synthesis in tetrahydrofuran resulted in crystalline β-Li3PS4 whereas acetonitrile led to amorphous Li3PS4. Annealing at 140 °C increased the Li+ conductivity of an amorphous composite (Li3PS4 + 1 wt % PEO) by 3 orders of magnitude (e.g., from 4.5 × 10-9 to 8.4 × 10-6 S/cm at room temperature) because of: (i) removal of coordinated solvent and (ii) rearrangement of the polyanionic network to form P2S74- and PS43- moieties. The PEO content in these composites should be limited to 1-5 wt % to ensure reasonable Li+ conductivity (e.g., up to 1.1 × 10-4 S/cm at 80 °C) while providing enough binder to facilitate scalable processing. The results of this study highlight a new strategy to suppress crystallization in sulfide-based SEs, which has important implications for solid-state batteries.
Original language | English |
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Pages (from-to) | 8789-8797 |
Number of pages | 9 |
Journal | Chemistry of Materials |
Volume | 32 |
Issue number | 20 |
DOIs | |
State | Published - Oct 27 2020 |
Funding
The authors thank Dr. Jianping Zheng and Dr. Annadanesh Shellikeri for supplying the thin Li foil used in the Li|SE|Li symmetric cells. This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and is supported by Asst. Secretary, Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (VTO) through the Advanced Battery Materials Research (BMR) Program. Electron microscopy and energy-dispersive X-ray spectroscopy studies were conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. This manuscript has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan ( http://energy.gov/downloads/doe-public-access-plan ). The authors thank Dr. Jianping Zheng and Dr. Annadanesh Shellikeri for supplying the thin Li foil used in the Li|SE|Li symmetric cells. This research was conducted at Oak Ridge National Laboratory, managed by UT Battelle, LLC, for the U.S. Department of Energy (DOE) and is supported by Asst. Secretary, Energy Efficiency and Renewable Energy (EERE), Vehicle Technologies Office (VTO) through the Advanced Battery Materials Research (BMR) Program. Electron microscopy and energy-dispersive X-ray spectroscopy studies were conducted at the Center for Nanophase Materials Sciences (CNMS), which is a DOE Office of Science User Facility. This manuscript has been authored in part by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the US Department of Energy (DOE). The publisher, by accepting the article for publication, acknowledges that the US government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this manuscript, or allow others to do so, for US government purposes. DOE will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).