cm5b04013_si_002.cif (1.51 kB)
Computational and Experimental Investigations of Na-Ion Conduction in Cubic Na3PSe4
dataset
posted on 2016-01-12, 00:00 authored by Shou-Hang Bo, Yan Wang, Jae Chul Kim, William
Davidson Richards, Gerbrand CederAll-solid-state Na-ion batteries
that operate at or close to room
temperature are a promising next-generation battery technology with
enhanced safety and reduced manufacturing cost. An indispensable component
of this technology is the solid-state electrolyte that allows rapid
shuttling of the mobile cation (i.e., Na+) between the
cathode and anode. However, there are very few fast Na-ion conductors
with ionic conductivity approaching that of the liquid counterparts
(i.e., 1 mS cm–1). In this work, we present the
synthesis and characterization of a fast Na-ion conductor, cubic Na3PSe4. This material possesses a room-temperature
ionic conductivity exceeding 0.1 mS cm–1 and does
not require high-temperature sintering to minimize grain boundary
resistance, making it a promising solid-state electrolyte candidate
for all-solid-state Na-ion battery applications. On the basis of density
functional theory, nudged elastic band, and molecular dynamics investigations,
we demonstrate that the framework of cubic Na3PSe4 only permits rapid Na+ diffusion with the presence of
defects, and that the formation of the Na vacancy (charge-balanced
by slight Se2– oxidation) is more energetically
favorable among the various defects considered. This finding provides
important guidelines to further improve Na-ion conductivity in this
class of materials.