Fig. 2: Operando SAXS/WAXS measurements.
a SAXS intensities versus scattering vector length q during potentiostatic discharge at 2.0 V vs. Li/Li+ up to a capacity of 1520 mAh gC–1. b The respective background corrected WAXS intensities versus scattering angle during potentiostatic discharge. The (111) and (200) Li2S diffraction peaks are fitted using a Lorentz function. c Specific current versus time during potentiostatic discharge/charge at 2.0 V / 2.45 V vs. Li/Li+. d The relative SAXS intensity change as a function time and the scattering vector length q. The SAXS intensities were normalized by the SAXS intensity prior to discharge at OCV. The q-regions qA and qB embrace intensity maxima that appear upon Li2S formation at low and high q, respectively. e The WAXS intensities as a function of time and scattering angle. The dash-dotted lines indicate the (111) and (200) Li2S diffraction peaks. f Normalized, mean SAXS intensity of the low-q (qA) and high-q (qB) regimes during potentiostatic discharge/charge (black and grey) and (111) diffraction peak integrated intensity in blue (obtained from Lorentzian peak fit). g Shift of the SAXS intensity maximum in qB, and Li2S crystallite size in blue (obtained from the (111) peak width and the Scherrer equation) during potentiostatic discharge/charge. Details on the quantification of the SAXS q-shift and the crystallite size are given in the Methods section.
