Through ab initio molecular dynamics theoretical calculations, we reveal that incorporation of excess halogen at sulfur site (4d) accelerates inter-cage jumps of Li+ with a low migration energy barrier. Subsequently, iodine-rich Li6−xPS5−xClIx (0 ≤ x ≤ 0.2) electrolytes with high ionic conductivity are successfully synthesized. Therefore, all-solid-state batteries with LPSC-0.1LiI electrolyte deliver excellent electrochemical properties.
Abstract:
Although iodine (I) doped Li6PS5Cl argyrodite sulfide electrolytes have attracted significant attention, a comprehensive understanding of how I− occupancy influences ionic conductivity is still lacking. Herein, through ab initio molecular dynamics theoretical calculations, it was revealed that the incorporation of excess halogen at the sulfur site (4d) significantly accelerates the inter-cage jumps of Li+ with a low migration energy barrier of 0.28 eV, enhancing the ionic diffusion kinetics. Subsequently, iodine-rich Li6−xPS5−xClIx (0 ≤ x ≤ 0.2) electrolytes are successfully synthesized and deliver high ionic conductivity. Moreover, a stable Li/Li6−xPS5−xClIx interface is achieved to inhibit side reactions and lithium dendrite growth. Therefore, Li symmetric cells with the optimized electrolyte present splendid cyclic stability (7000 h at 0.1 mAh cm−2 and 1500 h at 0.5 mAh cm−2). The constructed full cells with optimized electrolytes exhibit excellent electrochemical properties at a broad temperature range and with different active materials. This work deepens the understanding of the relationship between ion transport and structure in lithium argyrodite sulfide electrolytes.
Author list:
Zhikai Huang, Wenrui Sun, Shuaiyu He, Huan Hu, Xue Li, Ke Huang, Zhihao Yan, Gencai Guo, Yaojie Lei, Liwen Yang, Jianyu Huang, Gang Wang, Yaru Liang*, Guobao Xu*, Xingqiao Wu*
How to cite:
Z. Huang, W. Sun, S. He, H. Hu, X. Li, K. Huang, Z. Yan, G. Guo, Y. Lei, L. Yang, J. Huang, G. Wang, Y. Liang, G. Xu, X. Wu, Exploration 2025, 5, 20240050.
https://doi.org/10.1002/EXP.20240050