Hofmeister "Salting-In" Assisted Slurry Homogenization for Ultra-Thin Sulfide Solid-State Electrolytes

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Sulfide-based all-solid-state batteries (ASSBs) require ultra-thin electrolytes for high energy density and low impedance.
• Scalable fabrication of these electrolytes is hindered by binder/solvent incompatibility with sulfide solid-state electrolytes (SSEs).

Purpose of the Study:

• To develop a pioneering slurry-based strategy for dispersing binders in SSEs, expanding binder options for ASSB fabrication.
• To overcome limitations in scalable manufacturing of sulfide SSEs.

Main Methods:

• Utilized the Hofmeister "salting-in" effect to disperse binders in a poor-solvent environment.
• Employed Li-salts to uniformly disperse poly(vinylidenefluoride-trifluoroethylene-chlorotrifluoroethylene) (PVTC) in tetrahydrofuran, reducing aggregate size.
• Formed SSE/PVTC composite electrolytes (SCEs) with Li₆PS₅Cl slurry.

Main Results:

• Achieved ultra-low SCE resistance (0.69 Ω cm^-2) due to uniform PVTC dispersion and continuous polymer networks.
• Enhanced Li⁺-pathways and Li-salt dissociation via high-dielectric PVTC.
• Demonstrated ASSBs with >380 Wh kg^-1 energy density and 750 cycles with 80% capacity retention.

Conclusions:

• The slurry strategy effectively disperses binders, overcoming traditional limitations for sulfide SSEs.
• Rational structure design addresses transport obstructions, enabling efficient Li⁺ conduction.
• This breakthrough facilitates scalable ASSB production with enhanced performance and thermal management.