High air-stability and superior lithium ion conduction of Li3+3xP1-xZnxS4-xOx by aliovalent substitution of ZnO for all-solid-state lithium batteries

A series of new solid electrolytes of Li 3+3 x P 1- x Zn x S 4- x O x ( x = 0.01, 0.02, 0.03, 0.04, 0.05, 0.06) are synthesized successfully via Zn, O co-doping the Li 3 PS 4 glass-ceramic for the first time. The result shows that Li 3 PS 4 aliovalent substitution of 2 mol% ZnO (Li 3.06 P 0.98 Zn 0.02 S 3.98 O 0.02 ) presents the highest conductivity of 1.12×10 −3 S cm −1 at room temperature, which is twice that of the pristine Li 3 PS 4 . Besides, Li 3.06 P 0.98 Zn 0.02 S 3.98 O 0.02 exhibits excellent stability against humid air , lithium metal and chlorobenzene solvent. The mechanisms of the enhancement of conductivity and air-stability are well understood by conducting first-principles density functional theory (DFT) calculation and Bond-Valence (BV) analysis, and the results well demonstrate that the conductivity and air-stability of Li 3 PS 4 could be improved via Zn, O dual-doping, in which partial P 5+ could be substituted by Zn 2+ , and a part of S 2- could be replaced by O 2- . Finally, the all-solid-state lithium battery (ASSLB) with bi-layer electrolytes of LiCoO 2 /Li 10 GeP 2 S 12 /Li 3.06 P 0.98 Zn 0.02 S 3.98 O 0.02 /Li is assembled, and it delivers an initial discharge capacity of 139.1 mAh g −1 at 0.1 C and a capacity retention of 81.0% after 100 cycles at room temperature. This work combines systematical experimental characterizations and sufficient theoretical calculations to develop a new promising sulfide electrolyte with superior lithium ion conductivity and high air-stability for ASSLBs application.