Lithium-sulfur battery containing an electrode-protecting layer

A rechargeable alkali metal-sulfur cell selected from lithium-sulfur cell, sodium-sulfur cell, or potassium-sulfur cell, said alkali metal-sulfur cell comprising:

• (a) an anode active material layer and an optional anode current collector supporting said anode active material layer;
• (b) a cathode active material layer, comprising a sulfur-containing material selected from a sulfur-carbon hybrid, sulfur-graphite hybrid, sulfur-graphene hybrid, conducting polymer-sulfur hybrid, metal sulfide, sulfur compound, or a combination thereof, and an optional cathode current collector supporting said cathode active material layer;
• (c) an electrolyte and a porous separator layer;
• and
• (d) a discrete anode-protecting layer disposed between said anode active material layer and said porous separator and/or a discrete cathode-protecting layer disposed between the porous separator and the cathode active material layer;
• wherein said anode-protecting layer or cathode-protecting layer comprises a conductive sulfonated elastomer composite having from 0.01% to 40% by weight of a conductive reinforcement material and from 0.01% to 40% by weight of an electrochemically stable inorganic filler dispersed in a sulfonated elastomeric matrix material and said layer of conductive sulfonated elastomer composite has a thickness from 1 nm to 100 μm, a fully recoverable tensile strain from 2% to 500%, a lithium ion conductivity from 10−7 S/cm to 5×10−2 S/cm, and an electrical conductivity from 10−7 S/cm to 100 S/cm when measured at room temperature and wherein said inorganic filler has a lithium intercalation potential from 1.1 V to 4.5 V versus Li/Li+ and is selected from an oxide, carbide, boride, nitride, sulfide, phosphide, or selenide of a transition metal, a lithiated version thereof, or a combination thereof.