A self-assembled nanoporous polyelectrolytic interlayer for highly stable zinc metal anodes

Aqueous zinc-ion batteries (AZIBs) based on Zn metal anodes are promising candidates for next-generation energy storage due to their high performance, environmental friendliness, low cost, and high abundance. However, the excessive dendrite growth and continuous hydrogen evolution of Zn metal anodes in aqueous electrolytes severely deteriorate the electrochemical performance of AZIBs. Here, a highly stable Zn metal anode is designed by reconstructing its surface with a self-assembled nanoporous polyelectrolytic interlayer. This unique protective layer consisting of polyacrylic acid-zinc (PAAZn) nanospheres is highly hydrophilic and can act as a physical barrier to reduce the contact between Zn metal and water molecules, thus suppressing hydrogen evolution and Zn corrosion. Meanwhile, the unique nanostructures and chemical compositions of the PAAZn interlayer ensure fast Zn plating/stripping kinetics and facilitate the homogeneous growth of Zn deposits by redistributing Zn ion flux and local electric field at Zn/electrolyte interfaces. Therefore, symmetric cells based on the PAAZn-modified Zn metal anode ([email protected]) exhibited a significantly prolonged cycle life of 2,850 h and low voltage hysteresis. This work reports a uniquely designed nanoporous polyelectrolytic interlayer for highly reversible Zn metal anodes and provides a new strategy to enhance the electrochemical performance of AZIBs.