نبذة مختصرة : International audience ; Wide commercialization of Li-ion batteries (LIBs) for electric transport stimulates a demand for saferbatteries with higher energy density. Thiophosphate solid electrolytes (TSEs) for LIBs are one of the mostpromising candidates to replace a classical liquid electrolyte with volatile components owing to their highionic conductivity values and appropriate mechanical properties for processing [1]. However, one of themain drawbacks of TSEs is their high sensitivity towards humidity even in trace amounts. The reactivitywith water and moisture impacts the electrochemical properties of the electrolytes and leads to toxic H2Semissions. This aspect plays a crucial role for the choice of LIB manufacturing environment (dry roomcharacteristics) and requires fine understanding of underlying mechanisms to optimize a performance /cost ratio for solid-state batteries (SSBs).In the present study, a unique combination of characterisation methods was applied to investigate thereaction between densified Li3PS4 pellet and different levels of humidity (dew point (DP) -40 °C andDP=12 °C for 15 min and 2 h) from chemical and morphological/microstructural points of view. H2S gasevolution was accurately quantified upon a TSE exposure to humid atmosphere using a home-made flow-through setup with differentiation between surface and bulk pellet reactivity [2]. Further, top-viewpropagation of Li3PS4 pellet degradation was investigated using SEM and EDX techniques showingfractures generated through gas released leading to some increase in the pellet porosity at DP= -40 °C;apparition of cracks and oxygen content raise in case of DP = 12 °C exposure. The bulk of the exposedpellets was probed using non-destructive X-ray nanotomography (ESRF, ID16b). Different scenarios wereobserved at low and high levels of humidity during 15 min and 2 h of the pellet exposure (see Fig.).Degradation front containing large pores and cracks propagated up to 50 μm to the depth of the pellet(~400 μm total thickness) after 2 h of exposure to ...
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