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natalie@wfu.edu.
Fundamental aspects of the structural and electrolyte properties of
Li2OHCl from simulations and experiment
Jason Howard, Zachary D. Hood, and N. A. W. Holzwarth
Physical Review Materials 1 075406 (2017)
(local copy)
Solid-state electrolytes that are compatible with high-capacity electrodes are expected to enable the next
generation of batteries. As a promising example, Li2OHCl was reported to have good ionic conductivity and
to be compatible with a lithium metal anode even at temperatures above 100 ◦C. In this work, we explore
the fundamental properties of Li2OHCl by comparing simulations and experiments. Using calculations based
on density functional theory, including both static and dynamic contributions through the quasiharmonic
approximation, we model a tetragonal ground state, which is not observed experimentally. An ordered
orthorhombic low-temperature phase was also simulated, agreeing with experimental structural analysis of
the pristine electrolyte at room temperature. In addition, comparison of the ordered structures with simulations
of the disordered cubic phase provide insight into the mechanisms associated with the experimentally observed
abrupt increase in ionic conductivity as the system changes from its ordered orthorhombic to its disordered
cubic phase. A large Haven ratio for the disordered cubic phase is inferred from the computed tracer diffusion
coefficient and measured ionic conductivity, suggesting highly correlated motions of the mobile Li ions in the
cubic phase of Li2OHCl. We find that the OH bond orientations participate in gating the Li ion motions which
might partially explain the predicted Li-Li correlations.