Enhanced electrochemistry stability of oxygen doped Li6PS5Cl argyrodite solid electrolyte by liquid-phase synthesis

The argyrodite solid electrolyte Li6PS5Cl is one of the promising candidates due to its high Li-ion conductivity for the application of all-solid-state lithium-ion batteries (ASSLIBs). Unfortunately, Li6PS5Cl argyrodite exhibits low stability against lithium metal anodes and oxide cathodes. One way to improve stability is by oxygen doping into Li6PS5Cl argyrodite. In this work, Li6PS5–2.5xO2.5xCl (x = 0, 0.05, and 0.10) solid electrolytes with oxygen doping were successfully synthesized using liquid-phase synthesis for the first time. Therefore, the solid electrolyte with x = 0.05 exhibits high ionic conductivity with enhanced electrochemical stability against lithium metal and oxide cathodes. Argyrodites with x = 0.05 and x = 0.10 show superior capacity retention and higher Coulomb efficiency compared to x = 0. Moreover, the solid electrolytes also demonstrate better stability during Li symmetrical cell measurements. This experiment provides a controllable amount of oxygen doping into the Li6PS5Cl argyrodite solid electrolyte system in order to achieve high performance of ASSLIBs through liquid-phase synthesis.