The Complexation between Amide Groups of Polyamide-6 and Polysulfides in the Lithium-Sulfur Battery

Lithium-sulfur batteries have attracted considerable attention due to its high theoretical specific capacity, low cost, environmental friendliness, etc. However, the dissolution of polysulfide intermediate in the electrolyte leads to rapid capacity decay in the charge-discharge process. A sulfur-based cathode with the specific discharge capacity of 630 mAh g(-1) and ultrahigh capacity retention ratio of 0.11% per cycle after 400 cycles at 0.5 C that simply blend the sublimed sulfur and acetylene black in the mortar with the polyamide-6 (PA6) as binder is reported. The intense complexation between the lithium polysulfide and amide groups (-CO-NH-) in PA6 can effectively inhibit the "shuttling effect" and reduce the loss of active materials during the charge-discharge process. The discovery provides a handy and practicable strategy for developing the excellent cycling stability lithium-sulfur batteries.