Electrochemical polymerization of nonflammable electrolyte enabling fast-charging lithium-sulfur battery

Lithium-sulfur battery has received wide interest owing to its high theoretical energy density and abundant sulfur resources. Sulfurized pyrolyzed poly(acrylonitrile) ([email protected]) cathode can eliminate the shuttle effect owing to solid-solid conversion mechanism while suffers poor electrolyte/electrodes interphase and sluggish kinetics in carbonate electrolyte. Herein, an in-situ electrochemical polymerization is firstly proposed to form a nonflammable polyether electrolyte for [email protected] battery, which enables superior lithium compatibility (over 3000 h) and modifies the cathode interphase with promoted kinetics. The polyether-rich interphase ensures high capacity (1645.3 mAh g−1 based on sulfur), fast-charging ability (10 C) and remarkable cycling stability (99.5% retention over 400 cycles) with ultrahigh average Coulombic efficiency (CE) over 99.9995%, indicating nearly no irreversible reaction on cathode. The pouch cell delivers high sulfur utilization of 91.2% and stable performance with 84.6% capacity retention over 60 cycles.