Readme file for data relating to "Superionic lithium transport via multiple coordination environments defined by two anion packing"

Single crystal growth of Li7Si2S7I:
Crystals of Li7Si2S7I suitable for single crystal XRD were grown by crystallization of Li2S,
LiI and elemental Si reagents from the flux of elemental S in a graphite crucible in an evacuated
quartz ampoule. Stoichiometric amounts of Li2S (138 mg), LiI (134 mg), Si (56 mg), and S (128
mg) were ground in a mortar and pestle for 10 min, which were then pelletized and transferred into
a graphite crucible and sealed in an evacuated quartz ampoule (~10-5 mbar). The ampoule was then
heated to 723-773 K at heating rates of 5-10 K min-1, held for 2-12 days and cooled to room
temperature at a rate of 1 K min-1. The crystals suitable for single-crystal XRD were visually
identified and isolated from the resulting crystalline product.

High-purity Li7Si2S7I sample synthesis:
We used our own synthesized Li2S and SiS2 to prepare the sample to avoid any oxygen contamination.
To obtain a phase-pure sample, a mixture of Li2S (276 mg), LiI (268 mg), and SiS2 (387 mg)
was thoroughly ground with a mortar and pestle for 20 min, and then pelletized, placed in a
graphite crucible and vacuum-sealed in a quartz ampoule. The ampoule was heat treated at 723 K
for 2 days with a heating rate of 20 K min-1 and a cooling rate of 5 K min-1. The sample was then
reground and reheated under the same conditions but with a lower heating rate of 10 K min-1,
leading to a phase pure sample of Li7Si2S7I, which was characterized by synchrotron powder XRD
and Raman spectroscopy. Compositional analysis performed via CHNS and ICP-OES
confirmed that the composition of synthesized pure powder sample is consistent with
Li7Si2S7I determined from single crystal XRD. 

Single crystal X-ray diffraction:
The single crystal X-ray diffraction were carried out on beamline I19 at the Diamond Light Source 
in the UK using silicon double crystal monochromatic synchrotron radiation (λ = 0.6889 Å, Pilatus 2M detector).
The data were collected at five different temperatures, i.e., 100, 240, 300, 330, and 500 K.
Data reduction was performed with the CrysAlisPro (Version 171.40_64.53) software.
Files are readable in CrysAlisPro software which can be obtained free of charge upon registration at http://www.rigakuxrayforum.com/

Powder X-ray diffraction:
Synchrotron powder XRD was performed at the I11 beamline at Diamond Light Source (Oxfordshire, U.K.), with an incident wavelength 
of 0.825949 Å using a wide-angle position sensitive (PSD) detector and samples sealed in Ø = 0.5 mm borosilicate glass capillaries.
The synchrotron data is in .xye format and presented in a 3 column: 2Theta, counts and error.
Lab data was carried out using Rigaku SmartLab diffractometer with monochromatic Mo radiation (Kα1, λ = 0.7093 Å) 
and Bruker D8 Discover diffractometer with monochromatic Cu radiation (Kα1, λ = 1.540596 Å) in Debye−Scherrer transmission geometry.
The Lab data is in .raw format.

AC Impedance Spectroscopy:
AC impedance measurements were performed on Au|Li7Si2S7I|Au configuration using an impedance analyser (Keysight impedance analyser E4990A).
The experimental density of the sintered pellets was 96% of the theoretical maximum. 
A sputtered gold coating of ~2 nm thickness was used as the ion blocking electrodes.
Data were collected every 10 K from 237 to 373 K and were normalized for geometry of the pellets.
The data is in .z or .txt formats that is readable in ZView2 software which can be obtained at http://www.scribner.com

DC polarization:
DC polarization measurements were performed on a Au|Li7Si2S7I|Au symmetric cell using a Keithley 6430 Sub-Femtoamp Remote SourceMeter.
The data were collected at 303 K by applying constant bias voltages of 0.05, 0.1, 0.2 and 1 V for 4, 8, 12 and 20 h, respectively.
The measurements were performed until the current reached a steady state.
Data is presented in 4 column format: time(s) for whole measurement, time(s) for each bias voltages, current (A) and Voltage applied (V)

Galvanostatic Li plating and stripping:
The measurements were carried out on a Li|Li7Si2S7I|Li symmetric cell using a BioLogic VSP-300 Potentiostat.
The data were collected at room temperature (303 K) at current density of 0.05 mA cm−2 and 0.1 mA cm−2, respectively.
The data is in .mpr format that is readable in EC-Lab Software which can be obtained at https://www.biologic.net/support-software/ec-lab-software/?utm_source=NL&utm_medium=lien&utm_campaign=EC-Lab_update

All-solid-state lithium battery:
Galvanostatic charge and discharge measurements were performed using a BioLogic VSP-300 Potentiostat. 
The data was collected in a voltage range of 2.5-4.3 V vs. Li+/Li at room temperature at current density of 5 mA g-1.
The mass load of LiCoO2 is 4.9 mg cm−2.
The data is in .mpr format that is readable in EC-Lab Software which can be obtained at https://www.biologic.net/support-software/ec-lab-software/?utm_source=NL&utm_medium=lien&utm_campaign=EC-Lab_update

Cyclic voltammetry experiment:
The CV plating/stripping measurement were carried out on a “stainless steel (SS)|Li7Si2S7I|Li” cell using a BioLogic VSP-300 Potentiostat.
The data were collected at room temperature between -0.5 and 1 V vs. Li+/Li at a potential sweep rate of 0.1 mV s-1.
The data is in .mpr format that is readable in EC-Lab Software which can be obtained at https://www.biologic.net/support-software/ec-lab-software/?utm_source=NL&utm_medium=lien&utm_campaign=EC-Lab_update

Linear sweep voltammetry experiment:
The LSV measurement was carried out both on “stainless steel (SS)|Li7Si2S7I|Li” and “Li7Si2S7I + carbon fiber(CF)|Li7Si2S7I|Li” cell using a BioLogic VSP-300 Potentiostat.
The data were collected at room temperature from open circuit potential to 10 (for “stainless steel (SS)|Li7Si2S7I|Li” cell) and 8 V (for Li7Si2S7I + carbon fiber(CF)|Li7Si2S7I|Li) vs. Li+/Li.
The data is in .mpr format that is readable in EC-Lab Software which can be obtained at https://www.biologic.net/support-software/ec-lab-software/?utm_source=NL&utm_medium=lien&utm_campaign=EC-Lab_update

Raman spectroscopy:
Raman spectra were collected using an inVia Reflex Qontor Confocal Raman Microscope with 532 nm wavelength laser at room temperature.
Data is presented in 2 column fromat: Wavenumber/cm-1; Intensity/a.u.