New Insight for Solid Sulfide Electrolytes LSiPSI by Using Si/P/S as the Raw Materials and I Doping

Abstract

Solid sulfide electrolyte has been researched for several years, and a high ionic conductivity has been acquired. However, it is difficult to apply in industrial manufacturing partly because the raw materials, such as SiS 2 , GeS 2 , P 2 S 5 , et al., have strict preparing conditions and are sensitive to water and oxygen in the air. Herein, we report a new method to produce solid sulfide electrolytes Li 9.54 Si 1.74 P 1.44 S 11.7 X 0.3 (LSiPSX) (X = F, Cl, Br, I), that is, using elementary substances Si, P, and S as the starting raw materials, which not only is a promising way to ease the harsh storage conditions of the SiS 2 and P 2 S 5 as starting raw materials but also provides a feasible choice for the preparation of solid sulfide electrolyte. The conductivity of solid sulfide electrolyte is further adjusted by controlling the particle size of raw material silicon and the different halogen doping. As a result, the Li 9.54 Si 1.74 P 1.44 S 11.7 I 0.3 releases the highest ionic conductivity of 1.35 mS/cm at room temperature and a wide electrochemical window up to 9 V versus Li/Li + which is prepared from the 3 nm particle size Si and I doping. The all-solid-state lithium−sulfur battery (ASSLSB) is constructed with LSiPSI and with a good performance. Our study demonstrates the possibility of preparing the LGPS crystal type solid sulfide electrolytes by using elementary substances.

Sulfide and Oxide Inorganic Solid Electrolytes for All-Solid-State Li Batteries: A Review

“…This excellent ionic conductivity could be ascribed to the 3D conduction pathway for Li + ions. Later, Bai et al [297] Recently, Li et al [299] reported that the cells formed with a core-shell material, i.e., LiNi0.8Co0.1Mn0.1O2 (NMC-811) and LiNbO3-coated LiCoO2 (LNO@LCO), and Li9.54Si1.74P1.44S11.7Cl0.3 (73:27) pressed at 280 MPa, and a 10 mm Li-In alloy foil disk pressed at 300 MPa as the cathode active materials, solid electrolyte, and anode, respectively, presented good cycling stability. They used a cathode mass loading of approximately 14.0 mg cm −2 and voltage range of 2.1-3.8 V for their experiments.…”

“…This excellent ionic conductivity could be ascribed to the 3D conduction pathway for Li + ions. Later, Bai et al [ 297 ] synthesized Li 9.54 Si 1.74 P 1.44 S 11.7 X 0.3 ( X = F, Cl, Br, I) and reported that the conductivity of Li 9.54 Si 1.74 P 1.44 S 11.7 I 0.3 was high as 1.35 mS cm −1 . Choi et al [ 298 ] reported studies on electronic structures of Li 9.54 Si 1.74 P 1.44 S 11.7 I 0.3 by atomic simulation.…”

Lithium/Sulfide All‐Solid‐State Batteries using Sulfide Electrolytes

“…The analogical Li 9.54 Si 1.74 P 1.44 S 11.7 I 0.3 recent was proved to not only have an ionic conductivity as high as 1.35 × 10 −3 S cm −1 but also possess a electrochemical window up to 9 V versus Li/Li + . [ 38 ] Therefore, the LGPS‐type electrolytes are becoming one of the most attractive solid electrolytes. To further enhance the electrochemical stability window, Li 9.42 Si 1.02 P 2.1 S 9.96 O 2.04 was synthesized by the introduction of oxygen into the LGPS‐type structure which exhibited an ionic conductivity of 3.2 × 10 −4 S cm −1 .…”

“…[ 43 ] The sulfide electrolytes like Li 7 P 2.9 Mn 0.1 S 10.7 I 0.3 and Li 9.54 Si 1.74 P 1.44 S 11.7 I 0.3 exhibited a wide voltage stability up to 5 V and 9 V (vs Li/Li + ) tested by the same methods. [ 22,38 ]…”

Recent progress of sulfide electrolytes for all-solid-state lithium batteries

“…Initially, the electrochemical stability window of sulfides was measured by cyclic voltammetry. Early experiments demonstrated that most sulfide electrolytes possess a remarkable electrochemical stability window up to 5 V vs. Li metal [27,75,101,102] . For instance, the electrochemical window of Li 6 PS 5 X (X = Cl, Br or I) argyrodites was characterized by Boulineau et al [27] with a Li/BM-Li 6 PS 5 X/stainless steel cell.…”