Li1.5Al0.5Ge1.5(PO4)3 Ceramic Based Lithium-Sulfur Batteries with High Cycling Stability Enabled by a Dual Confinement Effect for Polysulfides

Graphical Closed borders : A Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) ceramic is adopted to block the migration of polysulfides in Li−S batteries, with solvent-in-salt wetting the electrode/ceramic interfaces. Owing to suppressed dissolution of polysulfides in SIS, the semi-solid-state Li−S batteries show superior capacity retention and long cycling life. Aimed at tackling the shuttle effect in lithium-sulfur (Li−S) batteries, a Li 1.5 Al 0.5 Ge 1.5 (PO 4 ) 3 (LAGP) ceramic is adopted to block the migration of polysulfides. However, the LAGP-based Li−S battery with liquid electrolyte wetting the interfaces still suffers from rapid capacity decay, as polysulfides tend to dissolve into liquid electrolyte and get firmly adsorbed by LAGP. In this work, a dual confinement effect for polysulfides is put forward, enabled by the LAGP ceramic and solvent-in-salt (SIS), wherein the SIS can greatly suppress the dissolution of polysulfides. Owing to the synergistic effect of SIS and LAGP, the semi-solid-state Li−S batteries show superior capacity retention and long cycling life. In particular, at a current density of 0.2 C, the Li−S battery with SIS-modified LAGP ceramic electrolyte delivers a high initial reversible capacity of 1251.7 mAh g −1 and long cycle life of over 250 cycles with a decay rate of only 0.07 % per cycle.