Leakage‐Proof Electrolyte Chemistry for a High‐Performance Lithium–Sulfur Battery

Electrolyte leakage is a severe safety concern in lithium batteries. With highly volatile 1,2‐dimethoxyethane as solvent, the leakage related hazards are more pronounced in lithium‐sulfur (Li‐S) batteries. To address this concern, a leakage‐proof electrolyte is delicately designed through functionalizing the commercial electrolyte by Li 6 PS 5 Cl‐grafted poly(ethyl cyanoacrylate), which can interact readily with the aluminum‐plastic packing through hydrogen bond to immobilize the electrolyte. The moisture from ambient can also catalyze a further polymerization of the macromolecules to seal the leaking points and thereby to solve the leakage issue, endowing Li‐S batteries superior safety even in an artificial cut pouch cell. With a bare S loading of 4.9 mg cm −2 , the battery can deliver good endurance owing to the suppressed polysulfide shuttle by its polar groups. This work enlightens the design of leakage‐proof electrolyte and makes a milestone for high performance Li‐S batteries.