Spatially Controlled Lithium Deposition on Silver‐Nanocrystals‐Decorated TiO₂ Nanotube Arrays Enabling Ultrastable Lithium Metal Anode

Abstract 3D scaffolds and heterogeneous seeds are two effective ways to guide Li deposition and suppress Li dendrite growth. Herein, 3D TiO₂ nanotube (TNT) arrays decorated using ultrafine silver nanocrystals (7–10 nm) through cathodic reduction deposition are first demonstrated as a confined space host for lithium metal deposition. First, TiO₂ possesses intrinsic lithium affinity with large Li absorption energy, which facilitates Li capture. Then, ultrafine silver nanocrystals decoration allows the uniform and selective nucleation in nanoscale without a nucleation barrier, leading to the extraordinary formation of lithium metal importing into 3D nanotube arrays. As a result, Li metal anode deposited on such a binary architecture (TNT‐Ag‐Li) delivers a high Coulomb efficiency at around 99.4% even after 300 cycles with a capacity of 2 mA h cm⁻². Remarkably, TNT‐Ag‐Li exhibits ultralow overpotential of 4 mV and long‐term cycling life over 2500 h with a capacity of 2 mAh cm^–2 in Li symmetric cells. Moreover, the full battery with 3D spaced Li nanotubes anode and LiFeO₄ cathode exhibits a stable and high capacity of 115 mA h g^–1 at 5 C and an excellent Coulombic efficiency of ≈100% over 500 cycles.