Halide Superionic Conductors for All-Solid-State Batteries: Effects of Synthesis and Composition on Lithium-Ion Conductivity.
ACS Energy Lett
; 9(5): 2212-2221, 2024 May 10.
Article
in En
| MEDLINE
| ID: mdl-38751969
ABSTRACT
Owing to their high-voltage stabilities, halide superionic conductors such as Li3YCl6 recently emerged as promising solid electrolyte (SE) materials for all-solid-state batteries (ASSBs). It has been shown that by either introducing off-stoichiometry in solid-state (SS) synthesis or using a mechanochemical (MC) synthesis method the ionic conductivities of Li3-3xY1+xCl6 can increase up to an order of magnitude. The underlying mechanism, however, is unclear. In the present study, we adopt a hopping frequency analysis method of impedance spectra to reveal the correlations in stoichiometry, crystal structure, synthesis conditions, Li+ carrier concentrations, hopping migration barriers, and ionic conductivity. We show that unlike the conventional Li3YCl6 made by SS synthesis, mobile Li+ carriers in the defect-containing SS-Li3-3xY1+xCl6 (0 < x < 0.17) and MC-Li3-3xY1+xCl6 are generated with an activation energy and their concentration is dependent on temperature. Higher ionic conductivities in these samples arise from a combination of a higher Li+ carrier concentration and lower migration energy barriers. A new off-stoichiometric halide (Li2.61Y1.13Cl6) with the highest ionic conductivity (0.47 mS cm-1) in the series is discovered, which delivers exceptional cycling performance (â¼90% capacity retention after 1000 cycles) in ASSB cells equipped with an uncoated high-energy LiNi0.8Mn0.1Co0.1O2 (NMC811) cathode. This work sheds light on the thermal activation process that releases trapped Li+ ions in defect-containing halides and provides guidance for the future development of superionic conductors for all-solid-state batteries.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
ACS Energy Lett
Year:
2024
Document type:
Article
Affiliation country:
United States