Effects of Grain Boundaries and Surfaces on Electronic and Mechanical Properties of Solid Electrolytes

Effects of Grain Boundaries and Surfaces on Electronic and Mechanical Properties of Solid Electrolytes

Xie, Weihang (National University of Singapore)
Deng, Zeyu (National University of Singapore)
Liu, Zhengyu (National University of Singapore)
Famprikis, T. (TU Delft RST/Storage of Electrochemical Energy)
Butler, Keith T. (University College London)
Canepa, Pieremanuele (National University of Singapore; University of Houston)

2024

Extended defects, including exposed surfaces and grain boundaries (GBs), are critical to the properties of polycrystalline solid electrolytes in all-solid-state batteries (ASSBs). These defects can alter the mechanical and electronic properties of solid electrolytes, with direct manifestations in the performance of ASSBs. Here, by building a library of 590 surfaces and grain boundaries of 11 relevant solid electrolytes—including halides, oxides, and sulfides— their electronic, mechanical, and thermodynamic characteristics are linked to the functional properties of polycrystalline solid electrolytes. It is found that the energy required to mechanically “separate” grain boundaries can be significantly lower than in the bulk region of materials, which can trigger preferential cracking of solid electrolyte particles in the grain boundary regions. The brittleness of ceramic solid electrolytes, inferred from the predicted low fracture toughness at the grain boundaries, contributes to their cracking under local pressure imparted by lithium (sodium) penetration in the grain boundaries. Extended defects of solid electrolytes introduce new electronic interfacial states within bandgaps of solid electrolytes. These states alter and possibly increase locally the availability of free electrons and holes in solid electrolytes. Factoring effects arising from extended defects appear crucial to explain electrochemical and mechanical observations in ASSBs.

electronic properties
first-principles calculations
grain boundaries
mechanical properties
solid electrolytes
surfaces

http://resolver.tudelft.nl/uuid:da4cbf15-21c8-474a-b79e-47e3a067778d

https://doi.org/10.1002/aenm.202304230

1614-6832

Advanced Energy Materials

Institutional Repository

journal article

© 2024 Weihang Xie, Zeyu Deng, Zhengyu Liu, T. Famprikis, Keith T. Butler, Pieremanuele Canepa