Double-sided engineering for space-confined reversible Zn anodes

Achieving stable Zn anodes with high depth of discharge (DOD) will promote the energy density of rechargeable Zn-ion batteries for practical applications, but still remains a great challenge. Herein, we report a double-sided engineering strategy for stable Zn anodes, where the top layer inhibits corrosion and hydrogen production and promotes Zn2+ flux, and the bottom layer stabilizes electron transport paths, reduces stress concentrations and accelerates local heat transfer. Such double-sided engineering synergistically generates a space-confined reversible Zn deposition behavior, which effectively improves Zn plating/stripping reversibility at high DOD. As a result, the developed anode can be stably cycled for more than 300 h at a high DOD of 85.5%. A stable NVO-based full cell exhibits high specific energy density (177.1 W h kg-1, based on the whole mass of electrodes) and high volumetric energy density (202.3 W h L-1, based on the whole cell), paving a good way for achieving practical Zn-ion batteries. Zn anodes with double-sided engineering are rationally designed and facilely constructed, which generates a space-confined reversible Zn deposition behavior, thus enabling stable Zn anode working at high depth of discharge with high energy density.