Deciphering the critical role of interstitial volume in glassy sulfide superionic conductors
Han Su, Yu Zhong, Changhong Wang, Yu Liu, Yang Hu, Jingru Li, Minkang Wang, Longan Jiao, Ningning Zhou, Bing Xiao, Xiuli Wang, Xueliang Sun, Jiangping Tu
Abstract
Abstract Sulfide electrolytes represent a crucial category of superionic conductors for all-solid-state lithium metal batteries. Among sulfide electrolytes, glassy sulfide is highly promising due to its long-range disorder and grain-boundary-free nature. However, the lack of comprehension regarding glass formation chemistry has hindered their progress. Herein, we propose interstitial volume as the decisive factor influencing halogen dopant solubility within a glass matrix. We engineer a Li 3 PS 4 -Li 4 SiS 4 complex structure within the sulfide glassy network to facilitate the release of interstitial volume. Consequently, we increase the dissolution capacity of LiI to 40 mol% in 75Li 2 S-25P 2 S 5 glass. The synthesized glass exhibits one of the highest ionic conductivities among reported glass sulfides. Furthermore, we develop a glassy/crystalline composite electrolyte to mitigate the shortcomings of argyrodite-type sulfides by utilizing our synthesized glass as the filler. The composite electrolytes effectively mitigate Li intrusion. This work unveils a protocol for the dissolution of halogen dopants in glass electrolytes.