Facet‐Engineered ZnO as an Interfacial Regulator for Stable Lithium Metal Anodes

ABSTRACT Interfacial instability remains the primary obstacle to realizing high‐energy Li‐metal batteries (LMBs). Here, we demonstrate that ZnO can function not as a conventional anode material but as a facet‐engineered interfacial regulator that stabilizes Li‐metal deposition. Using electrothermal‐wave (ETW) processing, we precisely modulate atomic diffusion kinetics to tailor the crystal facet orientation and morphology of ZnO nanostructures on carbon fibers. This controllable platform enables decoupling the facet‐ and morphology‐dependent effects on interfacial stability. Mechanistic analyses reveal that the semipolar (101) facet forms a conductive Li–Zn interface that promotes uniform Li nucleation and enables long‐term plating/stripping stability (>800 h), whereas the polar (002) facet generates an insulating Li ₂ O‐rich layer that impedes charge transfer. Concurrently, a 2D planar morphology enhances the electrochemically active surface area and exchange current density, yielding more favorable Li plating kinetics than 3D architectures. The optimized ZnO@CF electrode, integrating the (101)‐dominant facet and planar configuration, delivers stable reversibility in half‐cells and retains 80 % capacity over 200 cycles at 0.5 C in full‐cell pairing with a commercial NCM523 cathode. This study establishes a design framework where facet‐dependent interfacial reactivity and morphology‐dependent kinetic regulation act synergistically to stabilize reactive metal interfaces, offering a new paradigm for durable and efficient LMB anodes.