To exploit the high energy density of the lithium (Li) metal battery, it is imperative to address the dendrite growth and interface instability of the anode. 3D hosts for Li metal are expected to suppress the growth of Li dendrites. Heterogeneous seeds are effective in guiding Li deposition and realizing spatial control over Li nucleation. Herein, this study shows that ultrafine silver (Ag) nanoparticles, which are synthesized via a novel rapid Joule heating method, can serve as nanoseeds to direct the deposition of Li within the 3D host materials, resolving the problems of the Li metal anode. By optimizing the Joule heating method, ultrafine Ag nanoparticles (≈40 nm) are homogeneously anchored on carbon nanofibers. The Ag nanoseeds effectively reduce the nucleation overpotential of Li and guide the Li deposition in the 3D carbon matrix uniformly, free from the dendrites. A stable and reversible Li metal anode is achieved in virtue of the Ag nanoseeds in the 3D substrate, showing a low overpotential (≈0.025 V) for a long cycle life. The ultrafine nanoseeds achieved by rapid Joule heating render uniform deposition of Li metal anode in 3D hosts, promising a safe and long‐life Li metal battery for high‐energy applications.

Ultrafine Silver Nanoparticles for Seeded Lithium Deposition toward Stable Lithium Metal Anode