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.