Lithium Nafion-Modified Li 6.05 Ga 0.25 La 3 Zr 2 O 11.8 F 0.2 Trilayer Hybrid Solid Electrolyte for High-Voltage Cathodes in All-Solid-State Lithium-Metal Batteries.

All-solid-state batteries containing ceramic-polymer solid electrolytes are possible alternatives to lithium-metal batteries containing liquid electrolytes in terms of their safety, energy storage, and stability at elevated temperatures. In this study we prepared a garnet-type Li _6.05 Ga _0.25 La ₃ Zr ₂ O _11.8 F _0.2 (LGLZOF) solid electrolyte modified with lithium Nafion (LiNf) and incorporated it into poly(vinylidene fluoride- co -hexafluoropropylene) (PVDF-HFP) matrixes. We used a solution-casting method to obtain bilayer (Bi-HSE) and trilayer (Tri-HSE) hybrid solid electrolytes. A layer of functionalized multiwalled carbon nanotubes (f-MWCNTs) coated with LiNf (LiNf@f-MWCNT) in the Tri-HSE led to good compatibility with the polymer slurry and adhered well to the Li anode, thereby improving the interfacial contact at the electrode-solid electrolyte interface and suppressing dendrite growth. The Tri-HSE membrane displayed high ionic conductivity (5.6 × 10 ^-4 S cm ^-1 at 30 °C), a superior Li ⁺ transference number (0.87), and a wide electrochemical window (0-5.0 V vs Li/Li ⁺ ). In addition, Li symmetrical cells incorporating this hybrid electrolyte possessed excellent interfacial stability over 600 h at 0.1 mA cm ^-2 and a high critical current density (1.5 mA cm ^-2 ). Solid-state lithium batteries having the structure LiNf@LiNi _0.8 Co _0.1 Mn _0.1 O ₂ /Tri-HSE/Li delivered excellent room-temperature stable cycling performance at 0.5 C , with a capacity retention of 85.1% after 450 cycles.