Fast Ionic Conducting\nHydroxyapatite Solid Electrolyte\nInterphase Enables Ultra-Stable Zinc Metal Anodes

Abstract

Zn metal has been extensively utilized as an anode in\naqueous zinc-ion\nbatteries attributed to its affordable cost and superior theoretical\ncapacity. Nevertheless, the presence of dendrites and undesirable\nside reactions poses challenges to its widespread commercialization.\nTo address these issues, herein, a surface coating composed of hydroxyapatite\n(HAP) was developed on the Zn anode to create an artificial solid\nelectrolyte interphase. After the application of a hydroxyapatite\nlayer, dendrites and corrosion of the Zn anode are sufficiently inhibited.\nFurthermore, the hydroxyapatite interphase with a low ionic diffusion\nbarrier enables fast anodic redox kinetics. Consequently, the Zn@HAP\nsymmetric cell possesses a durable lifespan over 2000 h at 1 mA cm^–2, while maintaining minimal polarization. Moreover,\nthe practical feasibilities of the Zn@HAP anode are also manifested\nin full batteries combined with MnO₂ cathodes, exhibiting\nexceptional cycling performance up to 500 cycles at 1 A g^–1 and excellent rate capability with a retention of 109 mAh g^–1 at 5 A g^–1.