Binder-Free Sodium Zinc Phosphate Protection Layer Enabled Dendrite-Free Zn Metal Anode.

Aqueous Zn battery has been a promising alternative battery in large-scale energy storage systems due to its cost-effectiveness, sustainability, and intrinsic safety. However, its cycle life is impeded by the dendrite formation, severe corrosion, and side reactions on the zinc metal anode. Most ex situ coatings on the zinc surface extend the life span of zinc anodes but have drawbacks in Zn2+ ion conductivity. Herein, a robust sodium zinc phosphate layer was in situ built on zinc metal foil anode (Zn@NZP) via facile electrodeposition. The Zn2+ ion conducting protection layer alleviates corrosion, suppresses zinc dendrites, and lowers the energy barrier of Zn2+ plating and stripping. As a result, the Zn@NZP anode renders dendrite-free plating/stripping with a small overpotential of about 44 mV and a 12-fold enhancement long-life span compared to the bare zinc. Furthermore, a full cell using the Zn@NZP anode shows much improved capacity and cycling stability. This work provides a promising anode candidate for dendrite-free aqueous zinc ion batteries.

Facile and Rapid Synthesis of Porous Hydrated V2O5 Nanoflakes for High-Performance Zinc Ion Battery Applications.

Hydrated V2O5 with unique physical and chemical characteristics has been widely used in various function devices, including solar cells, catalysts, electrochromic windows, supercapacitors, and batteries. Recently, it has attracted extensive attention because of the enormous potential for the high-performance aqueous zinc ion battery cathode. Although great progress has been made in developing applications of hydrated V2O5, little research focuses on improving current synthesis methods, which have disadvantages of massive energy consumption, tedious reaction time, and/or low efficiency. Herein, an improved synthesis method is developed for hydrated V2O5 nanoflakes according to the phenomenon that the reactions between V2O5 and peroxide can be dramatically accelerated with low-temperature heating. Porous hydrated V2O5 nanoflake gel was obtained from cheap raw materials at 40 °C in 30 min. It shows a high specific capacity, of 346.6 mAh/g, at 0.1 A/g; retains 55.2% of that at 20 A/g; and retains a specific capacity of 221.0 mAh/g after 1800 charging/discharging cycles at 1 A/g as an aqueous zinc ion battery cathode material. This work provides a highly facile and rapid synthesis method for hydrated V2O5, which may favor its applications in energy storage and other functional devices.