Li₂ZnCu₃ Modified Cu Current Collector to Regulate Li Deposition

Abstract

Rationally designing a current collector that can maintain low lithium (Li) porosity and smooth morphology while enduring high-loading Li deposition is crucial for realizing the high energy density of Li metal batteries, but it is still challengeable. Herein, a Li₂ZnCu₃ alloy-modified Cu foil is reported as a stable current collector to fulfill the stable high-loading Li deposition. Benefiting from the in situ alloying, the generated numerous Li₂ZnCu₃@Cu heterojunctions induce a homogeneous Li nucleation and dense growth even at an ultrahigh capacity of 12 mAh cm^-2. Such a spatial structure endows the overall Li₂ZnCu₃@Cu electrode with the manipulated steric hindrance and outmost surface electric potential to suppress the side reactions during Li stripping and plating. The resultant Li||Li₂ZnCu₃@Cu asymmetric cell preserves an ultrahigh average Coulombic efficiency of 99.2 % at 3 mA cm^-2/6 mAh cm^-2 over 200 cycles. Moreover, the Li-Li₂ZnCu₃@Cu||LiFePO₄ cell maintains a cycling stability of 87.5 % after 300 cycles. After coupling with the LiCoO₂ cathode (4 mAh cm^-2), the cell exhibits a high energy density of 407.4 Wh kg^-1 with remarkable cycling reversibility at an N/P ratio of 3. All these findings present a doable way to realize the high-capacity, dendrite-free, and dense Li deposition for high-performance Li metal batteries.