Garnet-type solid-state electrolytes are a promising fast lithium-ion conductor due to their high room-temperature ion conductivity and inherent stability against lithium metal. However, interfacial lithiophobic Li₂CO₃ makes garnet/Li interfacial ionic contact challenging. The general approach to physically or chemically eliminating Li₂CO₃ inevitably leads to a Li-deficiency layer at the garnet surface, significantly retarding interfacial ion transport. Contrary to the aforementioned approach, herein we chemically upcycle the Li₂CO₃ on the garnet surface via the double replacement reaction between Li₂CO₃ and SiO₂. This approach in-situ constructs an air-stable and lithiophilic Li_xSiO_y (LSO) on the garnet surface and averts the Li-deficiency layer formation. The LSO modified symmetric cell displays a low interfacial impedance of 3 Ω cm² and a high critical current density of 1.2 mA cm⁻² at 30 ⁰C. This work provides a promising strategy to upcycle interfacial Li₂CO₃ on the garnet electrolyte.

石榴石型固态电解质是一种很有前途的快速锂离子导体，因为它们具有高室温离子电导率和对锂金属的固有稳定性。然而，界面疏锂的Li ₂ CO ₃使得石榴石/Li界面离子接触具有挑战性。物理或化学消除 Li ₂ CO ₃的一般方法不可避免地会在石榴石表面产生缺锂层，从而显着阻碍界面离子传输。与上述方法相反，本文通过 Li 2 CO 3 之间的双重置换反应对石榴石表面的Li ₂ CO ₃进行化学_上循环_。和SiO ₂。这种原位方法在石榴石表面上构建了空气稳定且亲锂的 Li _x SiO _y (LSO)，并避免了缺锂层的形成。LSO 改性的对称电池在 30 ^{0 C 时显示出 3 Ω cm 2}的低界面阻抗和 1.2 mA cm ^-2的高临界电流密度。这项工作为在石榴石电解质上循环界面 Li ₂ CO _{3提供了一种有前景的策略。}