One-Nanometer-Thick Interfaces of Titania Nanosheets for Reversible Zn-Metal Electrodes

Zinc-based aqueous energy storage technology has sparkedwidespreadinterest because of its low cost, high energy density, high safety,and environmentally benign manufacturing process. However, progresshas been severely impeded by H-2 evolution and Zn dendriteformation. Interfacial engineering is a promising avenue for addressingthese issues. Herein, molecularly thin Ti0.87O2 nanosheets were deposited on a Zn electrode surface via spin coatingto form a monolayer film with a thickness of & SIM;1 nm. The electrodesurface was fully covered with neatly tiled Ti0.87O2 nanosheets and thus effectively suppressed the H-2 evolution side reaction and reduced the Zn nucleation potential,resulting in uniform electrochemical deposition and reversible plating/strippingof Zn. As a consequence, the cycle life was drastically improved from105 to over 1400 h at 1 mA cm(-2)/1 mAh cm(-2). This study has established an economical and efficient molecular-scaleinterfacial engineering strategy enabling practical applications ofZn metal electrodes, and it also shows great promise for use withother metal electrodes in Li, Na, Al, and Mg metal batteries.