Fig. 1: Operando and ex situ scattering, electrochemical and microscopy measurements.

a Sketch of the experimental set-up for operando SAXS / WAXS measurements carried out at the international research centre ELETTRA62 showing the separate detectors. b Absolute specific current (blue) and absolute specific capacity (grey) versus time during potentiostatic discharge/charge of the operando SAXS cell at 2.0 V / 2.45 V vs. Li/Li+ at a temperature of 25 °C ± 3 °C. Both current and capacity are normalized by the bare carbon black electrode mass. c Ex situ scanning electron microscopy images at different magnification show the hierarchical structure of Li2S deposits on the carbon black electrode after potentiostatic discharge at 2.0 V vs. Li/Li+ to a capacity of 1520 mAh gC−1.