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Avinash Dongare1 Jin Wang2 Arthur Dobley3 C Carter1 4

1, University of Connecticut, Storrs, Connecticut, United States
2, University of Pennsylvania, Philadelphia, Pennsylvania, United States
3, Eaglepicher Technologies, East Greenwich, Rhode Island, United States
4, Sandia National Laboratories, Albuquerque, New Mexico, United States

The design/discovery of layered materials for applicability in next-generation battery technologies requires a fundamental understanding of the links between the atomic-scale structure, chemistry and the mechanisms and energetics of intercalation and de-intercalation reactions, and a consideration of other solid-state reactions that might compete. The goal of our research is to design/discover layered material microstructures as alternatives to graphite using an innovative combination of atomic-scale modeling, experimental in-situ characterization of the microstructural evolution during (de)intercalation reactions. Density functional theory (DFT) simulations are carried out to investigate the structural accommodation of the layered material during insertion and exertion of the intercalating species (energy barriers, volumetric expansion, and phase transformations). The structural stability of the 2H and 1T phases of MoS2 during lithiation suggests that a phase transformation of the 2H phase of MoS2 to the 1T phase may occur when MoS2 is reacted with Li; the computational study allows different dosages of Lithium ion to be assessed with the aim of testing these the validity of these models using in-situ characterization of the solid-state reactions between Li and MoS2 in the transmission electron microscope (TEM). The mechanisms of strain relaxation and the energetics of Li intercalation-induced phase transformations in MoS2 at the atomic scales will be presented. This work is supported by NSF grant No. 1820565.

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