Hofmeister “Salting‐In” Assisted Slurry Homogenization for Ultra‐Thin Sulfide Solid‐State Electrolytes

Abstract Sulfide‐based all‐solid‐state batteries (ASSBs) demand ultra‐thin electrolytes to achieve low impedance and high energy density, yet scalable fabrication remains bottlenecked by the incompatibility between binder/ solvent and sulfide solid‐state electrolytes (SSEs). Here, we introduce a pioneering slurry‐based strategy leveraging Hofmeister “salting‐in” effect to disperse binders in a poor‐solvent environment, dramatically expanding the applicable binder spectrum. The copolymer poly(vinylidenefluoride‐trifluoroethylene‐chlorotrifluoroethylene) (PVTC) was uniformly dispersed in tetrahydrofuran via Li‐salts mediation, reducing chain aggregate to hundreds of nanometers. PVTC with reduced size was homo‐dispersed in the Li 6 PS 5 Cl slurry, enabling the film‐formation of SSE/ PVTC composite electrolytes (SCEs) with an ultra‐low resistance of 0.69 Ω cm −2 , synchronously facilitating the formation of continuous polymer networks to provide mechanical cushioning that stabilizes interfaces during cycling. The high dielectric PVTC enhances Li‐salts dissociation, eradicating conduction barriers and establishing efficient Li + ‐pathways. Notably, the excellent thermal transfer capability of SCEs enables direct lamination onto electrodes, enabling industrial manufacturing. ASSBs featuring LiNi 0.8 Co 0.1 Mn 0.1 O 2 cathodes and silicon‐based anodes exhibited energy densities exceeding 380 Wh kg −1 and retained 80% capacity over 750 cycles. This work breakthrough traditional binder limitations for sulfide SSEs, addresses the transport obstruction through rational structure design, and ushers in a new era for scalable ASSB production.