Magnetohydrodynamic Interface‐Rearranged Lithium Ions Distribution for Uniform Lithium Deposition and Stable Lithium Metal Anode

Uneven lithium (Li) electrodeposition hinders the wide application of high‐energy‐density Li metal batteries (LMBs). Current efforts mainly focus on the side‐reaction suppression between Li and electrolyte, neglecting the determinant factor of mass transport in affecting Li deposition. Herein, guided Li+ mass transport under the action of a local electric field near magnetic nanoparticles or structures at the Li metal interface, known as the magnetohydrodynamic (MHD) effect, are proposed to promote uniform Li deposition. The modified Li+ trajectories are revealed by COMSOL Multiphysics simulations, and verified by the compact and disc‐like Li depositions on a model Fe3O4 substrate. Furthermore, a patterned mesh with the magnetic Fe−Cr2O3 core‐shell skeleton is used as a facile and efficient protective structure for Li metal anodes, enabling Li metal batteries to achieve a Coulombic efficiency of 99.5 % over 300 cycles at a high cathode loading of 5.0 mAh cm−2. The Li protection strategy based on the MHD interface design might open a new opportunity to develop high‐energy‐density LMBs. Uniformly deposited: Rearranged Li+ motions under the action of a local electric field near magnetic structures imbedded Li surfaces are proposed to promote mass transport for uniform Li deposition. A patterned mesh with magnetic Fe−Cr2O3 core‐shell skeleton is used as a facile and efficient protective structure of Li metal anode, enabling Li metal batteries to achieve a Coulombic efficiency of 99.5 % over 300 cycles at a high cathode loading of 5.0 mAh cm−2.