Consolidation of composite cathodes with NCM and sulfide solid-state electrolytes by hot pressing for all-solid-state Li metal batteries

Journal Article · 20 January 2022 · Journal of Solid State Electrochemistry

DOI: https://doi.org/10.1007/s10008-021-05104-8 · OSTI ID:2326215

Yersak, Thomas A.  ^[1]; Hao, Fang ^[2]; Kang, Chansoon ^[2]; Salvador, James R. ^[3]; Zhang, Qinglin ^[3]; Malabet, Hernando Jesus Gonzalez ^[2]; Cai, Mei ^[3]

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1. General Motors Global R&D, Warren, MI (United States); General Motors Global R&D
2. Optimal Inc, Plymouth, MI (United States)
3. General Motors Global R&D, Warren, MI (United States)

In this study, hot pressing was evaluated as a method of cell fabrication to increase the energy density of next-generation all-solid-state batteries with NCM active material and sulfide solid-state electrolyte. Hot pressing involves consolidating glassy sulfide electrolyte by the application of pressure at a temperature above the electrolyte’s glass transition temperature. Typically, cell stacks are formed at room temperature and retain 15–30% porosity that limits cell energy density. On the other hand, the porosity of hot-pressed cell stacks is reduced to less than 10%. The electrochemical function of hot-pressed cathode composites was assessed as a function of active material and solid-state electrolyte compositions. Specifically, LiNi_0.85Co_0.10Mn_0.05O₂ and LiNi_0.6Co_0.2Mn_0.2O₂ were studied in combination with either glassy Li₇P₃S₁₁, glassy Li₃PS₄, or β-Li₃PS₄ solid-state electrolytes. Cathode composites composed of LiNi_0.6Co_0.2Mn_0.2O₂ and Li₃PS₄ maintained the best function after hot pressing at 200 °C and 370 MPa for 10 min. It was found that LiNi_0.6Co_0.2Mn_0.2O₂’s resistance to microcracking and the inherent stability of Li₃PS₄’s fully de-networked local structure are critical to maintain good electrochemical function after hot pressing. Furthermore, the results of this study show that hot pressing reduces porosity in the cathode composite and confirms the feasibility of cathode support of consolidated, reinforced glass separators.

• Research Organization: General Motors Global R&D, Warren, MI (United States)
• Sponsoring Organization: USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO)
• Grant/Contract Number: EE0008857
• OSTI ID: 2326215
• Journal Information: Journal of Solid State Electrochemistry, Journal Name: Journal of Solid State Electrochemistry Journal Issue: 3 Vol. 26; ISSN 1432-8488
• Publisher: Springer NatureCopyright Statement
• Country of Publication: United States
• Language: English