Ultrastable Zinc Anodes Achieved by Hydroxyapatite Nanowire Coatings

Aqueous zinc-ion batteries (ZIBs) are promising for next-generation energy storage due to their low cost, high capacity, and safety. However, zinc anode issues such as dendrite growth and side reactions hinder their performance. This study introduces a hydrophilic hydroxyapatite (HAP) nanowire coating on zinc anodes to address these challenges. The three-dimensional porous HAP layer enhances wettability, provides abundant Zn2+ transport channels, homogenizes electric field distribution and Zn2+ deposition, and acts as a physical barrier against electrolyte contact, significantly suppressing side reactions. Symmetric cells with HAP@Zn anodes achieved exceptional stability, cycling over 1200 h at 1 mA cm–2 and 300 h even at 10 mA cm–2. HAP@Zn||Cu half-cells maintained a high average Coulombic efficiency of 99.48% over 1500 cycles at 5 mA cm–2. Furthermore, HAP@Zn||MnVO full cells delivered an outstanding rate capability and remarkable long-term stability, retaining 98.92% capacity after 2000 cycles at 3 A g–1. This work presents a simple, low-cost strategy for realizing ultrastable, dendrite-free zinc anodes, paving the way for high-performance and durable aqueous ZIBs with promising future applications.