Superdurable Aqueous Zinc-Ion Batteries Enabled by Multifunctional Hydrophilic Coatings

Dendrite growth occurs in zinc-ion batteries, hydrogen precipitation reactions, corrosion, and passivation on the surface of the zinc anode, which collectively compromise their cycling stability and reversibility. Here, multifunctional poly(norbornene dicarboxylic anhydride)/barium titanate (PNDA/BaTiO₃) coatings were developed as a protective film on the zinc anode via a spin-coating technique. Flexible and hydrophilic PNDA is capable of accommodating volume changes at the zinc-coated interface resulting from repeated deposition and stripping of zinc ions. Meanwhile, the directional electric field produced by BaTiO₃ with a spontaneous polarization effect significantly enhances the electrodeposition of zinc ions. Remarkably, the PNDA/BaTiO₃-0.50@Zn symmetric cell undergoes stable cycling for more than 12,000 h at a current density of 0.5 mA cm⁻², which is 60 times that of the Bare Zn symmetric cell. Correspondingly, the Coulombic efficiency of the PNDA/BaTiO₃-0.50@Cu half-cell is still maintained at around 99% after 600 cycles. Furthermore, the full cell, constructed by pairing the PNDA/BaTiO₃-0.50@Zn anode with the MnO₂ cathode, demonstrates a stable specific capacity of 120 mA h g⁻¹ over 1000 cycles at a current density of 1 A g⁻¹. This work develops a synergistic interfacial modulation strategy integrating hydrophilic PNDA coatings and BaTiO₃-induced electric field homogenization to achieve exceptional cycling stability in zinc-ion batteries. This work provides valuable insights into rational interface engineering for highly durable zinc-ion battery anodes.