Direct Observation of Interfacial Mechanical Failure in Thiophosphate Solid Electrolytes with Operando X‐Ray Tomography. Issue 19 (12th August 2020)

• Record Type: Journal Article
• Authors: Madsen, Kenneth E.; Bassett, Kimberly L.; Ta, Kim; Sforzo, Brandon A.; Matusik, Katarzyna E.; Kastengren, Alan L.; Gewirth, Andrew A.
• Is Part Of: Advanced materials interfaces. Volume 7:Issue 19(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-08-12
• Subjects: Li10GeP2S12 (LGPS) -- mechanical failure -- solid electrolytes -- solvates -- X‐ray tomography; Materials science -- Periodicals; 620.11
• DOI: 10.1002/admi.202000751
• Languages: English
• ISSNs: 2196-7350

Abstract

Abstract: Herein, the mechanical behaviors of Li10 GeP2 S12 (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. Abstract : Herein, the interfacial mechanical properties of the solid electrolyte (SE) Li10 GeP2 S12 are interrogated with operando X‐ray tomography. The origin of mechanical failure in SE pellets is revealed to be the electrochemical decomposition of the SE at the electrode/electrolyte interface. Further, the electrochemical and mechanical instabilities can be suppressed by the application of a liquid interlayer to the interface.