Sb and O dual doping of Chlorine-rich lithium argyrodite to improve air stability and lithium compatibility for all-solid-state batteries

Chlorine-rich lithium argyrodites with ultrahigh ionic conductivity show great potential as solid electrolytes in all-solid-state batteries, while the poor moisture and lithium metal compatibility limit their applications. Here, by tailoring Sb and O dual dopant, Li5.5P0.96Sb0.04S4.40O0.10Cl1.5 electrolyte delivers a high Li-ion conductivity up to 7.20 mS cm-1, excellent air/moisture and lithium metal endurance. The improved air stability is due to the strong Sb-S and P-O bonds in the co-doped electrolyte, inhibiting the reaction with water. While the enhanced lithium metal stability is attributed to the formation of the Li-Sb alloy layer, impeding the growth of lithium dendrites during cycling. The lithium symmetric cell using Li5.5P0.96Sb0.04S4.40O0.10Cl1.5 exhibits high critical current density (1.5 mA cm-2) and ultralong cyclability (750 h, 0.1 mA cm-2). The all-solid-state lithium metal battery using LiNi0.6Mn0.2Co0.2O2 cathode affords a high initial discharge capacity of 144.2 mAh g-1 at 0.1C. Moreover, the assembled battery shows a discharge capacity of 116.2 mAh g-1 at 0.5C and a capacity retention rate of 83.2% after 200 cycles. This work provides the guideline to design sulfide solid electrolytes that enable all-solid-state lithium metal batteries with high energy density and long cyclability.