Research progress of all-solid-state lithium–sulfur batteries with sulfide solid electrolytes: materials, interfaces, challenges, and prospects

Abstract

Lithium-sulfur batteries (LSBs) have attracted much attention due to their high energy density, environmental friendliness and abundant natural reserves, and are considered a strong competitor for the next generation of...

Effects of Lithium Halides on Electrode–Electrolyte Bifunctional Materials for High-Capacity All-Solid-State Batteries

“…These can improve the energy density of all-solid-state lithiumion batteries. 4,5 In particular, Li 2 S is attractive because of its high theoretical capacity (1167 mAh g −1 ) and relatively low cost. 6,7 In addition, all-solid-state cells using Li 2 S in the positive electrode start cycling from charging, which means that a Li source is not needed in the negative electrode.…”

“…All-solid-state lithium-ion batteries are attractive because of their safety and energy density, which are achieved by replacing the liquid electrolyte with inorganic solid electrolytes (SEs). − Among them, sulfur-based active materials have a high theoretical capacity as positive electrodes. These can improve the energy density of all-solid-state lithium-ion batteries. , In particular, Li 2 S is attractive because of its high theoretical capacity (1167 mAh g –1 ) and relatively low cost. , In addition, all-solid-state cells using Li 2 S in the positive electrode start cycling from charging, which means that a Li source is not needed in the negative electrode. Therefore, Li-free active materials such as silicon and carbon can be used for the negative electrode. , However, Li 2 S has low ionic and electronic conductivities of approximately 10 –9 S cm –1 and 10 –13 S cm –1 , respectively. , Therefore, Li 2 S must be mixed with conductive carbons − and sulfide SEs , to provide ionic and electronic conducting pathways. , However, the formation of composites decreases the active material ratio in the positive electrode, leading to a lower energy density.…”

Dendrite-Free Li5.5PS4.5Cl1.5-Based All-Solid-State Lithium Battery Enabled by Grain Boundary Electronic Insulation Strategy through In Situ Polymer Encapsulation

“…Highly polar solvents are typically strong Lewis bases containing electronegative elements such as N and O with lone pair electrons that tend to react with P 5+ in sulfide SSEs based on the theory of hard and soft acids and bases, and reaction products have low ionic conductivity. 12,26 There have been several successful attempts to combine polymers with sulfide SSEs. For example, our group 27 dispersed Li 6 PS 5 Cl particles in anhydrous acetonitrile solution of PEO to prepare Li 6 PS 5 Cl−x%PEO composite solid electrolytes (CSEs) with excellent mechanical property and high ionic conductivity.…”

“…As the core component of solid-state batteries, SSEs play a crucial role in connecting the cathode and anode, conducting lithium ions, and isolating electrons, which have been intensively researched in the past decade. , Among all SSEs, sulfide SSEs are the most popular due to their high ionic conductivity (∼10 –3 S cm –1 ), which is equivalent to that of liquid electrolytes while maintaining ductility, and have been widely studied. − Although sulfide electrolytes have better contact with Li metal compared with oxides and halides, there are still massive pores and cracks on the surface and interior of the electrolyte pellets, which initially lead to the nucleation of lithium dendrites and further growth of lithium dendrites. This creates stress in these pores, causing cracks and ultimately causing lithium dendrites to permeate the entire battery, resulting in battery failure. ,− Additionally, due to the inherent immobility of the sulfide SSEs, failure is inevitable around an area with contact defects at the interface between sulfide SSEs and the Li anode.…”

“…However, due to the high sensitivity of sulfide SSEs, the choice of solvents and polymer materials is very limited. Highly polar solvents are typically strong Lewis bases containing electronegative elements such as N and O with lone pair electrons that tend to react with P 5+ in sulfide SSEs based on the theory of hard and soft acids and bases, and reaction products have low ionic conductivity. , …”