Dendrite-Free Zinc Deposition Induced by Zinc-Phytate Coating for Long-Life Aqueous Zinc Batteries

Rechargeable aqueous zinc batteries (AZBs) have been recognized as attractive energy storage devices because of their intrinsic superiorities, e. g., high safety, low material cost and environmental benignity. However, challenges such as dendrite formation on the surface of zinc (Zn) anode, poor reversibility of Zn plating/stripping and short circuit of the cell, having detrimental impact on cycle life and safety, hinder their further development. Herein, we design an artificial solid electrolyte interphase (SEI) layer for the Zn anode by coating it with a zinc-phytate (ZP) layer via a facile acid-etching approach. The symmetric cell with a modified Zn electrode exhibits excellent cycling stability and a low polarization voltage, since the ZP layer can guide uniform Zn deposition under the layer without dendrite formation and maintain a smooth interface between separator and electrode, which suggests Zn2+ transport properties of the coating layer. Moreover, comparing full cells, one employing a bare Zn anode (MnO2/carbon nanofibers (CNFs)parallel to Zn), with the other with a modified Zn anode (MnO2/CNFs parallel to ZP-Zn), the MnO2/CNFs parallel to ZP-Zn cell delivers much better long-term cycling stability (capacity retention after 1000 cycles of 130 mAh g(-1) vs. 50 mAh g(-1) at a specific current of 0.5 A g(-1)). The coating via acid etching method offers a new powerful technique for further development of practical AZBs.