Abstract

Developing stable lithium metal battery (LMB) anodes remains a significant challenge due to severe volume changes and the formation of lithium dendrites. Herein, we report a dual-functional three-dimensional (3D) macroporous carbon host synthesized via a combined phase separation and sol-gel strategy. This strategy involves a spinodal decomposition process, driven by interactions between Zn²⁺ ions and poly(acrylic acid) (PAA), followed by a controlled gelation process using propylene oxide (PO). Upon carbonization, this process yields a macroporous 3D carbon framework embedded with ZnO nanoparticles (ZnO@MPC). The embedded ZnO nanoparticles act as nucleation seeds for uniform lithium plating, significantly reducing nucleation overpotential. Meanwhile, the interconnected macropores facilitate rapid Li⁺ diffusion into the internal structure, enabling homogeneous lithium metal growth throughout the 3D scaffold and enhancing host utilization. Electrochemical measurements demonstrate the excellent cycling stability of Li-plated ZnO@MPC electrodes in symmetric cells, as well as in Li metal full-cells under both plating-initiated and stripping-initiated configurations. Furthermore, this study proposes an in-situ electrochemical impedance spectroscopy (EIS) approach to assess lithium plating uniformity, showing that reduced resistance variation correlates with more homogeneous Li metal plating behavior.