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DOE OSTI · 1878615

Phase Stability of Garnet Solid-Electrolyte Interfacing with Various Cathodes in All Solid-State Batteries

Yu, Chan-Yeop·Choi, Junbin·Han, Jinhyup·Lee, Eungje·Kim, Jung-Hyun
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Abstract

Garnet-structured Li 6.75 La 3 Zr 1.75 Ta 0.25 O 12 (LLZTO) is one of the most promising electrolyte materials for solid-state Li batteries (SS-LiB). The design and fabrication of a good cathode/electrolyte interface is an important criterion for the SS-LiB. In this work, we performed a systematic study on the impact of cathode crystal structure and chemical compositions on their chemical stabilities against the LLZTO at elevated temperatures, which are required for their adhesion during cell fabrication processes. X-ray Diffraction (XRD) and Rietveld refinement analyses revealed the chemical stabilities of various cathode materials in contact with the LLZTO. While layered LiCoO 2 cathode showed good stability in contact with LLZTO to 900 °C, LiNiO 2 or Ni-rich LiNi x Mn y Co 1–x–y O 2 (NMC) cathodes suffered from the formation of La 4 NiLiO 8 due to La-diffusion from LLZTO. Furthermore, Mn-rich LiMn 2 O 4 spinel and layered LiNi 1/3 Mn 1/3 Co 1/3 O 2 cathodes suffered from the formation of La 2 Zr 2 O 7 due to Li-diffusion and production of Li 2 MnO 3 . As a result, LiNi 0.6 Mn 0.2 Co 0.2 O 2 , having an ideal balance of Ni/Mn/Co composition, or Li 2 MnO 3 containing cathodes such as Li 1.2 Ni 0.15 Mn 0.55 Co 0.1 O 2 were found to have excellent phase stability as the cathodes for LLZTO-based SS-LiBs.

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Yu, Chan-Yeop, Choi, Junbin, Han, Jinhyup, Lee, Eungje, Kim, Jung-Hyun. 2022-02-04. Phase Stability of Garnet Solid-Electrolyte Interfacing with Various Cathodes in All Solid-State Batteries. https://doi.org/10.1149/1945-7111%2Fac4e5b

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