A novel nanocomposite electrolyte with ultrastable interface boosts long life solid-state lithium metal batteries

Solid-state lithium metal batteries are promising next-generation battery systems, but their practical applications are hindered by the poor lithium ion transport kinetics in both the bulk solid electrolyte and electrolyte/electrode interface. A novel ZrO₂-based nanocomposite electrolyte by confining ionic liquids within the nanoscale ZrO₂ skeleton is reported, which is highly conductive for lithium ions both in the bulk phase and at the contact interface. Benefited from the fast transport of lithium ions, the nanocomposite electrolyte possesses a high ionic conductivity of 1.176 × 10⁻³ S cm⁻¹ at 30 °C. The electrolyte also shows excellent compatibility toward lithium metal anode and good resistance to lithium dendrites because of the uniform deposition of lithium ions influenced by the nanoparticles at interface. Furthermore, the solid-state batteries with different electrode materials, LiFePO₄, Li(Ni_1/3Mn_1/3Co_1/3)O₂, and Li₄Ti₅O₁₂, exhibit superior electrochemical stability and remarkable long-term cycling performance, verifying the usefulness of the nanocomposite electrolyte. These results indicate that this electrolyte has great promise for application in solid-state lithium metal batteries because of its dramatically enhanced conductive property and ultrastable interface.