Vulcanizable elastomer binders for high areal capacity rechargeable lithium–sulfur battery

Lithium–sulfur batteries possess excellent potential because of its about fivefold energy density promotion compared with traditional lithium-ion batteries. Nevertheless, further application has been hindered by rapid capacity attenuation largely result from the shuttle effect caused by intermediate polysulfides diffusion. Appropriate binders can play a crucial part of anchoring the lithium polysulfides in sulfur cathode through robust chemical bonds hence enhance the electrochemical performance of lithium–sulfur batteries. Herein, we explored a new type of binder (chloroprene rubber) that double bond is designed in the binder structure as the vulcanizable group which could significantly enhance the cycle performance of Li–S batteries. The evolution of the chemical bond and the effects of chemical structure of polymer binders were studied in detail. The resulting electrodes exhibit a high initial capacity of 5.43 mAh cm −2 and a reversible capacity retention of 4.06 mAh cm −2 after 120 cycles at 0.05 C, which is superior to Li–S battery with polyvinylidene fluoride (PVDF) binder. The improved performance is due to the vulcanizable double bonds, which has been demonstrated to efficaciously in situ anchoring the polysulfides to the S-cathodes by the breakage of C=C to form C–S bonds.