%0 Journal Article
%A Faka, Vasiliki
%A Samanta, Bibek
%A Lange, Martin A.
%A Helm, Bianca
%A Martinez de Irujo-Labalde, Xabier
%A Kierdorf, Niklas
%A Ketter, Lukas
%A Suard, Emmanuelle
%A Kraft, Marvin A.
%A Francisco, Brian E.
%A Hansen, Michael Ryan
%A Zeier, Wolfgang
%T Enhancing ionic conductivity in $Li_{6+ x} Ge_x P_{1−x}S_5Br$: impact of $Li^+$ substructure on ionic transport and solid-state battery performance
%J Journal of materials chemistry / A
%V 7
%@ 2050-7488
%C London ˜[u.a.]œ
%I RSC
%M FZJ-2025-02653
%P 17452-17466
%D 2025
%X Solid-state batteries have been investigated as efficient energy storage systems due to the increased power and energy densities that they can offer compared to liquid-based batteries. The search for solid electrolytes with high ionic conductivities, sufficient electrochemical and mechanical stability is indispensable. In this work, the $Li_{6+ x} Ge_x P_{1−x}S_5Br$ substitution series is investigated via X-ray and neutron powder diffraction, as well as impedance and solid-state nuclear magnetic resonance spectroscopy. Structural analyses reveal the expansion of the cage-like $Li^+$ substructure with increasing degree of substitution of Ge(IV) for P(V) in $Li_{6+ x} Ge_x P_{1−x}S_5Br$. Solid-state nuclear magnetic resonance spectroscopy measurements reveal the gradual changes in cation environments ($^6Li$ and $^{31}P$) and the effect of Ge(IV) substitution on local $Li^+$ transport. Impedance spectroscopy shows an improvement of ionic conductivity at room temperature up to fivefold for $Li_{6.31}Ge_{0.31}P_{0.69}S_5Br$ and decreasing activation energies. Employing $Li_{6.31}Ge_{0.31}P_{0.69}S_5Br$ as a catholyte in $LiNi_xMn_yCo_zO_2$ based solid-state batteries results in reproducibly higher active material utilization and rate stability in comparison to $Li_6PS_5Br$. This work emphasizes the importance of understanding the $Li^+$ substructure of argyrodites in correlation with the $Li^+$ transport properties to systematically develop highly conductive $Li^+$ solid electrolytes for improved solid-state batteries.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:001489149300001
%R 10.1039/D5TA01651G
%U https://juser.fz-juelich.de/record/1042707