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Direct Observation of Interfacial Mechanical Failure in Thiophosphate Solid Electrolytes with Operando X‐Ray Tomography
Author(s) -
Madsen Kenneth E.,
Bassett Kimberly L.,
Ta Kim,
Sforzo Brandon A.,
Matusik Katarzyna E.,
Kastengren Alan L.,
Gewirth Andrew A.
Publication year - 2020
Publication title -
advanced materials interfaces
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.671
H-Index - 65
ISSN - 2196-7350
DOI - 10.1002/admi.202000751
Subject(s) - electrolyte , materials science , electrochemistry , fast ion conductor , lithium (medication) , electrode , chemical engineering , chemistry , medicine , engineering , endocrinology
Abstract Herein, the mechanical behaviors of Li 10 GeP 2 S 12 (LGPS) solid electrolytes during electrochemical cycling using operando X‐ray tomography are investigated. It is demonstrated that the bulk mechanical decomposition of LGPS when cycled against lithium is a direct result of electrochemical reduction of the solid electrolyte at the LGPS/Li 0 interface. The reductive decomposition of LGPS during lithium plating results in the formation of low‐density domains at the electrode/electrolyte interface, which impose sufficient mechanical stress on the underlying LGPS to crack the SE pellet. The critical stress developed prior to pellet fracture is significantly lower than the bulk shear modulus of LGPS, suggesting that the electrochemical instability of LGPS dramatically worsens the mechanical stability of the material near the LGPS/Li 0 interface. It is also shown that the application of a highly concentrated liquid electrolyte to the LGPS surface suppresses the reductive decomposition of LGPS, improving both the electrochemical performance and mechanical stability of the bulk LGPS solid electrolyte.