Tuning Lithiophilic Sites of Ag-Embedded N-Doped Carbon Hollow Spheres via Intentional Blocking Strategy for Ultrastable Li Metal Anode in Rechargeable Batteries

Abstract

Li metal is regarded as an ultimate anode material for high-energy-density lithium-ion batteries; however, addressing dendritic deposi-tion and large volume changes during cycling is essential to commercialize the Li metal anodes. Herein, we propose Ag-embedded N-doped carbon/Li-ion conductor double-shelled hollow spheres (Ag@NC@LAZP) as an electrode material for selective Li deposition. When constructing hollow spheres for Li storage, the use of lithiophilic Ag nanoseeds and N-doped carbon (NC) layers lowers the nucleation overpotential, thereby facilitating uniform Li deposition. However, if the lithiophilic NC layer is exposed outside the hollow spheres, Li may grow outside the hollow spheres. Therefore, the application of a Li1.5Al0.5Zr1.5(PO4)3 (LAZP) outer layer is effective for the complete deposition of Li into the spherical inner space by blocking the exposed lithiophilic sites. The stable Li plating/stripping of the Ag@NC@LAZP electrode was achieved by the Li-ion conductive LAZP outer layer, and accordingly, dendritic growth was eliminated and improved cycling with 98.2% Coulombic efficiency for more than 450 cycles was observed. Covering lithiophilic sites and guiding Li deposition through the Li-ion conductive layer are effective for achieving stable Li metal anodes.