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

Zinc-based aqueous energy storage technology has sparked widespread interest because of its low cost, high energy density, high safety, and environmentally benign manufacturing process. However, progress has been severely impeded by H2 evolution and Zn dendrite formation. Interfacial engineering is a promising avenue for addressing these issues. Herein, molecularly thin Ti0.87O2 nanosheets were deposited on a Zn electrode surface via spin coating to form a monolayer film with a thickness of ∼1 nm. The electrode surface was fully covered with neatly tiled Ti0.87O2 nanosheets and thus effectively suppressed the H2 evolution side reaction and reduced the Zn nucleation potential, resulting in uniform electrochemical deposition and reversible plating/stripping of Zn. As a consequence, the cycle life was drastically improved from 105 to over 1400 h at 1 mA cm–2/1 mAh cm–2. This study has established an economical and efficient molecular-scale interfacial engineering strategy enabling practical applications of Zn metal electrodes, and it also shows great promise for use with other metal electrodes in Li, Na, Al, and Mg metal batteries.