Trapping lithium polysulfides of a Li-S battery by forming lithium bonds in a polymer matrix

Despite great interest in a Li-S battery, soluble polysulfides as charge/discharge intermediates pose an important challenge to realize commercial Li-S batteries. For building physical barriers to reduce a diffusional loss of those species, chemical surfacetrap- sites have been proposed, but experimental evidence about the trapping interaction hasn't been reported. Here, highly crosslinked polymer-electrolyte coating layers with electron-donating groups were designed to bind lithium polysulfides. An ester group with a high spatial density was shown to be a strong candidate to bind lithium polysulfides. Spectroscopic evidence for the presence of lithium bonds between the lithium polysulfides and the electrondonating groups is reported for the first time. An electrochemical charge/discharge model is also proposed, which can explain the electrochemical behavior within the insulating polymer layer.