Li-ion all-solid-state batteries promise to enhance safety and performance compared to conventional liquid based batteries. Nevertheless, only few investigations have been carried out on the effect of the solid electrolyte’s ionic conductivity on the electrochemical performance of batteries in order to visualize non-uniform fields of transport.

Neutron Imaging (NI) is a non-intrusive technique that offers the possibility of tracking light elements such as the ⁶Li isotope during all phases of battery operation. Because it helps visualizing lithium’s concentration profiles, NI allows quantifying Li-ion transport and enables us to model solid state batteries. We therefore expect NI to help us explain solid state batteries’ poor rate capabilities. A reliable electrochemical cell was successfully designed and utilized for an operando test of an all-solid-state battery using PSI's high-resolution neutron imaging detector ('Neutron Microscope') at the POLDI beamline of Swiss Spallation Neutron Source SINQ (Paul Scherrer Institut). A solid state battery with a composite electrode TiS₂:⁶Li₃PS₄(⁶LPS) and a ⁶Li-In alloy counter electrode have been investigated (Figure 1) and the results will be discussed.