Dynamic interface layer enables epitaxial Li deposition for anode-free Li metal batteries

Abstract

Anode-free Li-metal batteries are the best high-energy-density Li-ion batteries. However, the lack of active Li on anode side exacerbates dendritic Li growth, dead Li formation and parasitic reactions. In this study, we develop a lithiophilic Mg modification layer on Cu foil surface using magnetron sputtering. The epitaxial and dense Li deposition are manipulated, attributing to excellent Li affinity, favorable charge transfer and self-diffusion kinetics of the functional layer. Consequently, the coulombic efficiency of Li deposition/stripping on the Mg-coated Cu substrate remains at 83.7 % even after 50 cycles under 0.5 mA cm⁻². Importantly, this approach enable the pouch cells paired with LiFePO₄ cathodes to achieve a lifespan of over 70 cycles under 0.5 mA cm⁻² without experiencing a significant capacity drop. This straightforward strategy is promising for developing long-lasting anode-free Li batteries.