Oxygenated Li3PS4 Electrolyte with improved Conductivity and Air Stability for All-Solid-State Li–ion Batteries

Abstract

All solid-state Lithium–ion battery (ASSLB) is a promising energy storage device, owing to its high-energy density and safety. In this work, we report a Li₃PS_1–xO_x by O-doped β–Li₃PS₄ using planetary ball-milling method. As-prepared Li₃PS_1–xO_x is utilized as a solid electrolyte (SE) for the ASSLB. Experimental observation including electrochemical impedance spectroscopy (EIS), air stability, and electrochemical tests reveal that the small amount of O-doping into β–Li₃PS₄ can abruptly improve the ionic conductivity, air stability, and electrochemical properties. x=0.2 amount of O-doping (Li₃PS_3.8O_0.2) exhibits high ionic conductivity of 1.13 mS·cm⁻¹, which is 2.56 times higher than that of the un-doped β–Li₃PS₄ (0.44 mS·cm⁻¹). Meanwhile, H₂S suppression of Li₃PS_3.8O_0.2 is 10 times higher than that of the β–Li₃PS₄. Different kinds of anode material (Li, In, and Li–In) for the Li₃PS_3.8O_0.2 glass–ceramic SE with the Li (Ni₀.₈Co₀.₁Mn_0.1)O₂ (NCM811) as cathode is proposed for the fabrication of the ASSLB cell. The NCM811/Li₃PS_3.8O_0.2/Li–In delivered higher reversible capacity and better rate performances than the NCM811/Li₃PS₄/Li–In ASSLB, owing to O-incorporation. These results reveal that the partial replacement of S²⁻ with O²⁻ could improve the ionic conductivity, air stability, and improve the electrochemical performances of β–Li₃PS₄.