Chemistry

Metallurgy

Materials science

Optoelectronics

Electrochemistry

Engineering

Composite material

Geometry

Physics

Electrode

Coating

Dendrite (mathematics)

Anode

Nanotechnology

Current density

Mathematics

Zinc

Anodizing

Quantum mechanics

Metal

Chemical engineering

Faraday efficiency

Physical chemistry

Aluminium

Advanced Functional Materials

Here, an electrode comprising a Zn hexagonal pyramid array (HPA) coated with a functionalized ZnO layer (Zn@ZnO HPA) is prepared using a periodic anodizing technique. The HPA structure markedly increases the electroactive surface area of Zn anode, thus decreasing the local current density. Furthermore, the functionalized ZnO coating layer has a gradient thickness that plays an important role in the selective deposition of Zn ions and the mitigation of side reactions at the interface. The electrochemical stability of the Zn@ZnO HPA electrode, which is closely related to the electroactive surface area and charge transfer resistance, is determined by the “split” value, i.e., ratio of current‐off to current‐on time, a parameter of the periodic anodizing process. Compared with the pristine Zn‐based symmetric cell, the Zn@ZnO HPA‐based symmetric cell is safely operated in the investigated experimental range with the 10‐fold improved running life and 25‐fold enhanced current density without Zn dendrite growth. Moreover, the Zn@ZnO HPA/MnO 2 battery exhibits outstanding long‐term cyclability (nearly 100%) with greater than 99% Coulombic efficiency after 1000 cycles at a current density of 9 A g −1 . This periodic anodizing technique for ultrastable Zn metal anodes is expected to contribute to the development of inherently safe energy storage systems.

Functionalized Zn@ZnO Hexagonal Pyramid Array for Dendrite‐Free and Ultrastable Zinc Metal Anodes