| 초록 |
All-solid-state rechargeable lithium-ion batteries are attractive power sources for electrochemical applications due to their potential to improve safety and stability compared to conventional batteries with liquid electrolytes. Finding a solid electrolyte with high ionic conductivity and compatibility with other battery components is a key factor in increasing the performance of any solid LIB. Several structural and chemical families of solid LIB conductors such as LGPS, LISICON and Argyrodites have been shown to exhibit ionic conductivity spanning over 10mS/cm at room temperature (RT). And Lithium argyrodites make up a promising family of solid state electrolytes, characterized by the general composition of Li7-y-x[(A1-y/By)C4]C1-xX1+x (A, B, C and X denote elements of group IV, V, VI and VII, respectively) Here, we present systematic exploration of descriptors for computational screening of the argyrodite-based solid state superionic conductors. Argyrodite consist of polyanions and single anions surrounded by cage-like Li ion diffusion network. We found that the ionic conductivity has strong correlation with the disorderedness of single anions and the size of the Li-ion cage formed around the single anions. Especially, when the Li-ion cages are of uniform size, the inter-cage diffusion for higher ionic conductivity is accelerated. Therefore, we proposed the uniformity of Li-ion cage size as a screening descriptor for argyrodite-based solid state superionic conductors. The proposed our results will provide insights into the development of new compositions of argyrodite. |
