Titanium-Oxygen Clusters Brazing Li with Li_6.5La₃Zr_1.5Ta_0.5O₁₂ for High-Performance All-Solid-State Li Batteries

Garnet-based solid-state electrolytes are considered crucial candidates for solid-state Li batteries due to their high Li⁺ conductivity and nonflammability; however, poor interfacial contact with the Li anode and growth of Li dendrites limit their application. Herein, a high-activity titanium-oxygen cluster is used as a brazing filler to braze the Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZTO) with an Li anode into the whole unit. The brazing layer leads to a significantly lower interfacial impedance of 8.32 Ω cm². Furthermore, the brazing layer is an isotropic amorphous ion-electron hybrid conductive layer, which significantly promotes Li⁺ transport and regulates the distribution of the electric field, therefore inhibiting the growth of Li dendrites. The cell exhibits an ultrahigh critical current density of 2.3 mA cm^-2 and stable cycling of over 4000 h at 0.5 mA cm^-2 (25 °C).