Stabilizing Li₁₀SnP₂S₁₂/Li Interface via an in Situ Formed Solid Electrolyte Interphase Layer

Abstract

Despite the extremely high ionic conductivity, the commercialization of LiGePS-type materials is hindered by the poor stability against Li metal. Herein, to address that issue, a simple strategy is proposed and demonstrated for the first time, i.e., in situ modification of the interface between Li metal and LiSnPS (LSPS) by pretreatment with specific ionic liquid and salts. X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy results reveal that a stable solid electrolyte interphase (SEI) layer instead of a mixed conducting layer is formed on Li metal by adding 1.5 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)/ N-propyl- N-methyl pyrrolidinium bis(trifluoromethanesulfonyl)imide (PyrTFSI) ionic liquid, where ionic liquid not only acts as a wetting agent but also improves the stability at the Li/LSPS interface. This stable SEI layer can prevent LSPS from directly contacting the Li metal and further decomposition, and the Li/LSPS/Li symmetric cell with 1.5 M LiTFSI/PyrTFSI attains a stable cycle life of over 1000 h with both the charge and discharge voltages reaching about 50 mV at 0.038 mA cm. Furthermore, the effects of different Li salts on the interfacial modification is also compared and investigated. It is shown that lithium bis(fluorosulfonyl) imide (LiFSI) salt causes the enrichment of LiF in the SEI layer and results in a higher resistance of the cell upon a long cycling life.

High-performance all-solid-state batteries enabled by salt bonding to perovskite in poly(ethylene oxide)

“…3D. The Li/composite interfacial resistance decreased from 595 to 90 Ω cm 2 after 10 h, indicating the formation of a stable solid electrolyte interphase between the metallic Li anode and the composite electrolyte (32)(33)(34). A similar phenomenon of a decreased Li/composite interfacial resistance was also observed for the symmetric cell without the lithium plating-stripping process (SI Appendix, Fig.…”

Zinc anode-compatible in-situ solid electrolyte interphase via cation solvation modulation

“…The Cl-containing solutions, however, are corrosive to common battery components especially at high operation voltages, and are not readily available in forming a stable and ionically conducting interphase for Zn anodes. As an alternative anion to form DESs, TFSI − is generally considered to be a decomposition source to promote the formation of uniform SEI and thus has aroused our concern 12,32 . Besides, the binding energy of TFSI − to metal ions appears to be relatively lower compared with those of other conventional anions such as BF 4 − , PF 6 − , allowing the TFSI-based salts to dissociate easily 33,34 .…”

Fast Charging Lithium Batteries: Recent Progress and Future Prospects

“…In addition, Al 2 O 3 coating layer is also employed to effectively reduce the interfacial resistance . Recently, constructing a buffer‐layer by in situ interface modification strategies is effective to improve the surface stability . However, it still remains a challenge to construct a stable and efficient lithium metal/solid electrolyte interface.…”