Application of Rod-Like Li₆PS₅Cl Directly Synthesized by a Liquid Phase Process to Sheet-Type Electrodes for All-Solid-State Lithium Batteries

Abstract

All-solid-state lithium batteries employing sulfide-based solid electrolytes have emerged as promising next-generation batteries for large-scale energy storage applications because of their safety and high energy density. Among them, Li 6 PS 5 X (X = Cl, Br, I) with an argyrodite structure synthesized by planetary milling exhibits a rather high lithium ion conductivity of 10 −2 -10 −3 S cm −1 at room temperature. Unfortunately, the planetary milling process has the disadvantage of producing the solid electrolytes with large, round-shaped particles. Recently, the solid electrolytes have been synthesized by not the mechanical milling but the liquid-phase process, which facilitates synthesis of sub-micrometer-to nanometer-sized solid electrolyte particles. It is important to reduce the particle size of the solid electrolyte to promote intimate contact with the active material in the composite cathode. Here, rod-like Li 6 PS 5 Cl solid electrolyte with a high ionic conductivity of 1.1 × 10 −3 S cm −1 at room temperature was, for the first time, directly prepared by a liquid phase process using only a stirring method. SEM images showed the electrolyte had a rod-like morphology with a length of 20-30 μm and a width of 2-3 μm. The composite cathode was prepared from a slurry and the cell performances were investigated.

Sustained Release‐Driven Formation of Ultrastable SEI between Li6PS5Cl and Lithium Anode for Sulfide‐Based Solid‐State Batteries

“…The electrochemical impedance spectroscopy (EIS) measurement is conducted and the calculated ionic conductivity of LPSC at 25 °C is 2.44 × 10 −3 S cm −1 (Figure 2c). The activation energy of LPSC acquired by the linear fitting in Figure 2d is 0.333 eV (Table S1, Supporting Information), which is similar to the reported literatures, [19] indicating that the as-prepared SSE shows a stable intrinsic chemical property. [20] And the porous structure of LPSC was examined by scanning electron microscopy (SEM) and the corresponding element composition was confirmed by energy dispersive X-ray spectroscopy (EDS) ( Figure S1, Supporting Information).…”

“…The intercept at the high‐frequency range represents bulk resistance ( R SSE‐b ) of LPSC, while the semicircle can be attributed to sum of the grain‐boundary impedance ( R SSE‐gb ) and interfacial resistances between Li and LPSC. The total resistance ( R SSE ) of LPSC ( R SSE = R SSE‐b + R SSE‐gb ) [ 19 ] of LPSC in the cell with bare Li is higher than another two (about 40 Ω) because of side reaction between Li foils and LPSC as mentioned before. [ 23 ] Meanwhile, the evident resistance at the PPC/Li interface could be identified through the comparative analysis of PPC @ Li based symmetric cell and PPC @ SS based symmetric cell, which is mainly caused by in situ formed interface when introduced PPC contacts Li.…”

Impact of Solvent Treatment of the Superionic Argyrodite Li6PS5Cl on Solid‐State Battery Performance

“…Argyrodites have also been used with xylenes, mineral spirit, and dibromomethane in slurry processes. [ 28,45–50 ] The formation of a SE suspension was reported to slightly affect the conductivity, [ 28,45,46 ] while still improving cell performance compared with dry mixing [ 28 ] or noncoated active material. [ 47 ] Unlike Li 3 PS 4 , [ 10,51 ] argyrodites can be dissolved in alcohols for infiltration processes by using ethanol or mixtures of ethanol with ethyl acetate, ethyl propionate, THF, or ACN.…”

“…[ 19,54,56,57 ] For argyrodites treated in ethanol, the grain boundary resistance was reported to increase due to surface residues originating from the solvent. [ 45,56,57 ] Furthermore, partial decompositions of the argyrodite, indicated by the presence of Li 2 S and LiCl after recovery, were reported in a mixture of ethanol and ACN. [ 21 ] Nevertheless, ethanol seems to be a compatible solvent for solution syntheses of argyrodites, but compatibility with the argyrodite and other cathode components, e.g., binders or dispersants, seems to be strongly affected by the time of exposure and the conditions of the necessary subsequent heat treatment.…”

Interface engineering for composite cathodes in sulfide-based all-solid-state lithium batteries

“…Other electrolytes of the LGPS family (LSnPS, LSiPS, Li 9.54 Si 1.74 P 1.44 -S 11.7 Cl 0.3 ) are also prepared by solid-state sintering [62][63][64]. Recently, the wet-chemical method has received extensive attention as it can control morphology and scale up the production of sulfide solid electrolytes [91][92][93]. Xu et al [94] compared the Li 7 P 3 S 11 electrolytes synthesized through different solvents.…”