Magnetic-Field-Induced Synergistic Regulation of Lithium Deposition via Nucleation and Ion Transport Control in 3D Hosts

Lithium metal anodes (LMAs) are considered key candidates for next-generation high-energy-density batteries but are hindered by dendritic growth and severe interfacial instability. While three-dimensional (3D) hosts alleviate volume fluctuations, Li deposition is often restricted near the surface due to diffusion-limited ion transport. Herein, a magnetic-field-assisted 3D host is developed by codecorating a lithiophilic phase and a superparamagnetic phase on a porous Cu framework, denoted as ZFCu-3D. The lithiophilic component reduces the Li nucleation barrier, whereas the magnetic component, activated under an external magnetic field, facilitates depth-wise Li + transport through a magnetically assisted ion-transport effect. As a result, Li deposition becomes markedly more uniform throughout the host, accompanied by the formation of an inorganic-rich and stable solid electrolyte interphase layer. Benefiting from this synergistic regulation, the ZFCu-3D anode exhibits a low nucleation overpotential of only 17.1 mV at 3 mA cm –2 and stable operation for over 900 h at 1 mA cm –2 in symmetric cells, which is over three times longer than that of pristine Cu-3D. LiFePO 4 full cells further demonstrate improved rate capability and capacity retention. This work establishes an effective paradigm for coupling interfacial thermodynamics with field-assisted ion transport toward dendrite-free lithium metal anodes.