Phase Separation of Li 2 S/S at Nanoscale during Electrochemical Lithiation of the Solid‐State Lithium–Sulfur Battery Using In Situ TEM

S/Li2S phase separation at nanoscale is observed for the first time in the solid-state Li–S battery by using in situ transmission electron microscopy. This nanophase separation not only reduces the diffusion distance but also provides the S/Li2S interfaces network, which is favorable for electron and Li+ ion transportation during the lithiation process.