TY - JOUR
T1 - Ionic Conductivity of Nanocrystalline and Amorphous Li10GeP2S12
T2 - The Detrimental Impact of Local Disorder on Ion Transport
AU - Schweiger, Lukas
AU - Hogrefe, Katharina
AU - Gadermaier, Bernhard
AU - Rupp, Jennifer L.M.
AU - Wilkening, H. Martin R.
N1 - Publisher Copyright:
© 2022 American Chemical Society. All rights reserved.
PY - 2022/6/8
Y1 - 2022/6/8
N2 - Solids with extraordinarily high Li+dynamics are key for high performance all-solid-state batteries. The thiophosphate Li10GeP2S12(LGPS) belongs to the best Li-ion conductors with an ionic conductivity exceeding 10 mS cm-1at ambient temperature. Recent molecular dynamics simulations performed by Dawson and Islam predict that the ionic conductivity of LGPS can be further enhanced by a factor of 3 if local disorder is introduced. As yet, no experimental evidence exists supporting this fascinating prediction. Here, we synthesized nanocrystalline LGPS by high-energy ball-milling and probed the Li+ion transport parameters. Broadband conductivity spectroscopy in combination with electric modulus measurements allowed us to precisely follow the changes in Li+dynamics. Surprisingly and against the behavior of other electrolytes, bulk ionic conductivity turned out to decrease with increasing milling time, finally leading to a reduction of σ20°Cby a factor of 10. 31P, 6Li NMR, and X-ray diffraction showed that ball-milling forms a structurally heterogeneous sample with nm-sized LGPS crystallites and amorphous material. At -135 °C, electrical relaxation in the amorphous regions is by 2 to 3 orders of magnitude slower. Careful separation of the amorphous and (nano)crystalline contributions to overall ion transport revealed that in both regions, Li+ion dynamics is slowed down compared to untreated LGPS. Hence, introducing defects into the LGPS bulk structure via ball-milling has a negative impact on ionic transport. We postulate that such a kind of structural disorder is detrimental to fast ion transport in materials whose transport properties rely on crystallographically well-defined diffusion pathways.
AB - Solids with extraordinarily high Li+dynamics are key for high performance all-solid-state batteries. The thiophosphate Li10GeP2S12(LGPS) belongs to the best Li-ion conductors with an ionic conductivity exceeding 10 mS cm-1at ambient temperature. Recent molecular dynamics simulations performed by Dawson and Islam predict that the ionic conductivity of LGPS can be further enhanced by a factor of 3 if local disorder is introduced. As yet, no experimental evidence exists supporting this fascinating prediction. Here, we synthesized nanocrystalline LGPS by high-energy ball-milling and probed the Li+ion transport parameters. Broadband conductivity spectroscopy in combination with electric modulus measurements allowed us to precisely follow the changes in Li+dynamics. Surprisingly and against the behavior of other electrolytes, bulk ionic conductivity turned out to decrease with increasing milling time, finally leading to a reduction of σ20°Cby a factor of 10. 31P, 6Li NMR, and X-ray diffraction showed that ball-milling forms a structurally heterogeneous sample with nm-sized LGPS crystallites and amorphous material. At -135 °C, electrical relaxation in the amorphous regions is by 2 to 3 orders of magnitude slower. Careful separation of the amorphous and (nano)crystalline contributions to overall ion transport revealed that in both regions, Li+ion dynamics is slowed down compared to untreated LGPS. Hence, introducing defects into the LGPS bulk structure via ball-milling has a negative impact on ionic transport. We postulate that such a kind of structural disorder is detrimental to fast ion transport in materials whose transport properties rely on crystallographically well-defined diffusion pathways.
UR - http://www.scopus.com/inward/record.url?scp=85131771481&partnerID=8YFLogxK
U2 - 10.1021/jacs.1c13477
DO - 10.1021/jacs.1c13477
M3 - Article
C2 - 35608382
AN - SCOPUS:85131771481
SN - 0002-7863
VL - 144
SP - 9597
EP - 9609
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 22
ER -