Phosphatized garnet-based solid electrolyte enables a sub-10-μm-thick lithium metal anode

Lithium metal anodes are widely regarded as the ultimate solution for high-energy-density batteries. However, their practical application has been hindered by the challenge of simultaneously achieving ultrathin thickness and high Coulombic efficiencies during lithium deposition and stripping. To address this issue, we propose a phosphorization strategy involving the phosphorization of garnet-based solid electrolyte and subsequently the reaction with molten lithium. This lithium-phosphorus reaction markedly enhances the wettability of molten lithium on a copper current collector, enabling the fabrication of a sub-10-µm-thick ultrathin lithium metal anode. As a proof of concept, a 6-µm-thick ultrathin lithium metal anode demonstrates exceptional performance, achieving a Coulombic efficiency of over 98.8% at a substantial utilization rate of 83%. These findings provide a promising pathway toward the development of practical ultrathin lithium metal anodes for the next-generation batteries.