| 초록 |
All-solid-state batteries are receiving a lot of attention because of stability problems of conventional lithium-ion batteries. Argyrodites Li6PS5Cl is one of the candidate materials for all-solid-state rechargeable LIBs with a high Li-ion conductivity of almost 0.1 to 1 mS/cm. However, it is necessary to improve the Li-ion conductivity of this material to use in commercial LIBs. In this work, we theoretically elucidated the Li-ion conductivity significantly increased as the amount of halogen ions(X) are changed. We designed the stable phase of crystal structures by controlling ratio x in Li6-xS5-xX1+x. For all halogens, the structure with x=0.75 showed the highest Li-ion conductivity. We concluded that the increased ionic conductivity was due to forced anion disorder by the increase of halogen ions, reduced inter-cage distance, and increased lithium ion vacancies. Our results provide a theoretical halogen ratio that gives the best performance of argyrodite Li6-xS5-xX1+x. |
