Amorphous Dual-Layer Coating: Enabling High Li-Ion Conductivity of Non-Sintered Garnet-Type Solid Electrolyte

Publisher:
WILEY-V C H VERLAG GMBH
Publication Type:
Journal Article
Citation:
Advanced Functional Materials, 2021, 31, (15)
Issue Date:
2021-04-01
Full metadata record
Garnet-type oxide Li La Zr Ta O (LLZTO) has attracted considerable attention as a highly promising solid state electrolyte. However, its high ionic conductivity is achievable only after high temperature sintering (≈1200 °C) to form dense pellets but with detrimental brittleness and poor contact with electrodes. Herein, a novel strategy to achieve high Li ion conductivity of LLZTO without sintering is demonstrated. This is realized by ball milling LLZTO together with LiBH , which results in a LLZTO composite with unique amorphous dual coating: LiBO as the inner layer and LiBH as the outer layer. After cold pressing the LLZTO composite powders under 300 MPa to form electrolyte pellets, a high Li ion conductivity of 8.02 × 10 S cm is obtained at 30 °C, which is four orders of magnitude higher than that of the non-sintered pristine LLZTO pellets (4.17 × 10 S cm ). The composite electrolyte displays an ultrahigh Li transference number of 0.9999 and enables symmetric Li–Li cells to be cycled for 1000 h at 60 °C and 300 h at 30 °C. The significant improvements are attributed to the continuous ionic conductive network among LLZTO particles facilitated by LiBH that is chemically compatible and electrochemically stable with Li metal electrode. 6.4 3 1.4 0.6 12 4 2 4 4 + + –5 –1 –9 –1 +
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