Interface Design for High-Performance All-Solid-State Lithium Batteries

All-solid-state batteries suffer from high interface resistance and lithium dendrite growth leading to low Li plating/stripping Coulombic efficiency (CE) of <90% and low critical current density at high capacity. Here, simultaneously addresses both challenges are simultaneously addressed and the Li plating/stripping CE is significantly increased to 99.6% at 0.2 mA cm⁻²/0.2 mAh cm⁻², and critical current density (CCD) of > 3.0 mA cm⁻²/3.0 mAh cm⁻² by inserting a mixed ionic-electronic conductive (MIEC) and lithiophobic LiF-C-Li₃N-Bi nanocomposite interlayer between Li₆PS₅Cl electrolyte and Li anode. The highly lithiophobic LiF-C-Li₃N-Bi interlayer with high ionic conductivity (10⁻⁵ S cm⁻¹) and low electronic conductivity (3.4×10⁻⁷ S cm⁻¹) enables Li to plate on the current collector (CC) surface rather than on Li₆PS₅Cl surface avoiding Li₆PS₅Cl electrolyte reduction. During initial Li plating on CC, Li penetrates into porous LiF-C-Li₃N-Bi interlayer and lithiates Bi nanoparticles into Li₃Bi. The lithiophilic Li₃Bi and Li₃N nanoparticles in LiF-C-Li₃N-Li₃Bi sub-interlayer will move to CC along with plated Li, forming LiF-C/Li₃N-Li₃Bi lithiophobic/lithiophilic sublayer during the following Li stripping. This interlayer enables Co_0.1Fe_0.9S₂/Li₆PS₅Cl/Li cell with an areal capacity of 1.4 mAh cm⁻² to achieve a cycle life of >850 cycles at 150 mA g⁻¹. The lithiophobic/lithiophilic interlayer enables solid-state metal batteries to simultaneously achieve high energy and long cycle life.

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