A new halospinel superionic conductor for high-voltage all solid state lithium batteries

Abstract

A new disordered chlorospinel superionic conductor, Li2Sc2/3Cl4, enables high-voltage all solid state batteries up to 4.6 V vs. Li+/Li.

Tailoring the Cation Lattice for Chloride Lithium‐Ion Conductors

“…[42,43] According to our design principles and computation results of hypothetical Li-ion conductors, Li-ion conductivities of Li x MCl 4 materials can be improved by reducing cation concentrations. (Fd3m) reports greatly increased Li-ion conductivity to 1.5 mS cm −1 at RT, [25] confirming our computation predictions and the design principle of reducing cation concentration for increasing Li- A recent experimental study on LiAlCl 4 (P2 1 /c) suggests a Li-ion conductivity of 0.02 mS cm −1 at RT, higher than previously reported Li 2 MgCl 4 and Li 2 CdCl 4 , and supports our computation results about potential good Li-ion diffusion in these Li x MCl 4 systems. [44] Therefore, the strategies for improving ionic conductivity in common Li x MCl 4 systems are reducing cation concentrations or tailoring cation coordination, which deserve further study.…”

“…Our results further confirm recent computation and experimental studies that Li 3 MCl 6 are promising Li SICs for a wide range of cation and substitutions. [18][19][20][21][22][23][24][25] Most Li x MCl 4 and Li x M 1/2 Cl 4 materials even with substantial levels of substitution have Li-ion conductivities much lower than 200 mS cm −1 at 600 K, and 24 of 51 materials exhibit a negligible amount of Li-ion hopping to obtain a statistically reliable ionic diffusivity. There are a few Li-ion conductors as the exceptions in the Li x MCl 4 category, as a result of their distinct local cation coordination, which are further discussed in Section 3.…”

“…achieves high Li-ion conductivity of 1.5 mS cm −1 at RT, significantly higher than the original Li 2 MgCl 4 . [25] The increased…”

“…In addition, doping and substitutions on these chloride SICs to tune Li concentration and cation concentration were demonstrated to further improve ionic conductivities. [22][23][24][25] It is not clear why certain doping strategies lead to improved Li-ion conductivity. To rationally guide future materials design of new halide Li-ion conductors, a scientific understanding about the effects of cation concentration, cation configuration, and Li concentration on Li-ion conduction is needed.…”

“…[ 19 ] Recent experimental studies reported a series of Li‐containing chlorides Li 3 MCl 6 (M = In, Er, Sc) and their doped variations that achieved Li‐ion conductivities on the order of 1 mS cm −1 at RT. [ 19,21–25 ] While the discovery of new SIC systems in oxides and sulfides is greatly limited by the unique crystal structures required for achieving fast Li‐ion conduction, [ 26–28 ] Li‐containing chlorides with common fcc and hcp anion sublattices exhibit adequately low Li‐ion migration barrier, and are a promising chemical space for new Li‐ion conductors.…”