A self-assembled 2-hydroxyphosphonoacetic acid protective layer enables dendrite-free Zn anodes.

A stable self-assembled 2-hydroxyphosphonoacetic acid (HPAA) layer was constructed on the Zn surface via chelation. This HPAA protective layer significantly inhibits the water-related side reactions and suppresses Zn dendrite growth. Consequently, the Zn-HPAA-1h anode shows a long cycling lifetime of 650 h in a symmetric cell at 30.0 mA cm -2 . Also, the Zn-HPAA-1h//V 2 O 5 full cell demonstrates a high capacity of 154.1 mA h g -1 after 1000 cycles at 2 A g -1 . This study provides a new strategy for developing dendrite-free Zn anodes.