Na superionic conductor-type compounds as protective layers for dendrites-free aqueous Zn-ion batteries.

Aqueous rechargeable Zn-ion batteries (ARZIBs) have attracted much attention owing to their safety, high energy density and environmental friendliness. However, dendrite formation and corrosive reactions on Zn anode surface limit the development of ARZIBs. Here, Ga3+-doped NaV2(PO4)3 with Na superionic conductor (NASICON) structure [NVP-Ga(x), x = 0, 0.25, 0.5, 0.75] have been exploited as the high-efficiency artificial layer to stabilize Zn anode. The optimal NVP-Ga(0.5) layer can homogenize ion flux and promote uniform deposition of zinc, the dendrite growth and the parasitic reactions can be greatly inhibited. The symmetric cell based on this unique protection layer can stably operate over 1,300 h at 0.5 mA cm-2 with 0.5 mAh cm-2. Benefitting from the high-performance Zn metal anode, the full batteries paired with MnO2 cathode deliver a high discharge capacity of 106 mAh/g with the capacity retention rate of 85 % after 8,000 cycles. This work provides an advanced strategy to stabilize Zn anode for the industrialization of ARZIBs in the near future.