Accelerated Reversible Conversion of Li2S2 to Li2S by Spidroin Regulated Li+ Flux for High-performance Li-Sulfur Batteries

<p><span>Regulating the transformation of sulfur species is the key to improving the electrochemical performance of lithium-sulfur (Li-S) batteries, in particular, to accelerate the reversible conversion between solid phase Li₂S₂ and Li₂S. Herein, we introduced Spidroin, which is a main protein in spider silk, as a dual functional separator coating in Li-S batteries to effectively adsorb polysulfides via the sequence of amino acids in its primary structure and regulate Li⁺ flux through the &beta;-sheet of its&nbsp;secondary structure, thus accelerating the reversible transformation between Li₂S₂ and Li₂S. Spidroin-based Li-S cells exhibited an exceptional electrochemical performance with a high specific capacity of<span>&nbsp; </span></span><span>744.1</span><span> mAh g^-1 at </span><span>5</span><span>C and a high areal capacity of </span><span>7.5</span><span> mAh cm^-2 at a low electrolyte-to-sulfur (E/S) ratio of 6 &mu;L mg_s^-1 and a sulfur loading of </span><span>8.6</span><span> mgs cm^-2.</span></p>