Small molecules with adjustable sulfur atoms in the confined structure were acted as precursor for the synthesis of polymer cathodes for lithium-organosulfur batteries. Among them, poly(diallyl tetrasulfide) (PDATtS) delivered a high capacity of 700 mAh g?1, stable capacity retention of 85% after 300 cycles, high areal capacity ~ 4 mAh cm?2 for electrode with up to 10.3 mg cm?2 loading. New insight into the reaction mechanism of PDATtS electrode that radicals arisen from the homolytic cleavage of S?S bond in PDATtS reacted with Li+ to generate thiolates (RSLi) and insoluble lithium sulfides (Li2S) or lithium disulfide (Li2S2) was clearly verified by in-situ UV/Vis spectroscopy, nuclear magnetic resonance (NMR) studies and density-functional theory (DFT) calculations. Therefore, based on the unique reaction mechanism, problems of rapid capacity fading due to the formation of soluble polysulfide intermediates and their serious shuttle effect in conventional lithium–sulfur (Li–S) batteries was totally avoided, realizing the dendrite-free lithium sulfur batteries. This study sets new trends for avenues of further research to advance Li-S battery technologies.
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