Stable Zn metal anode enabled via ferroelectric nanotube arrays

Abstract

Aqueous zinc-ion batteries are receiving increasing attention owing to their markedly high safety and low cost. However, the uncontrolled zinc dendrite growth and the side reactions at Zn-electrolyte interfaces hinder the practical application of aqueous rechargeable zinc-based batteries. Therefore, regulating the electrode/electrolyte interface to achieve dense zinc deposition is crucial for improving the electrochemical performance of zinc-ion batteries. Herein, ferroelectric composite nanotube arrays (BaTiO3 modified TiO2 nanotubes, TiO2@BaTiO3) are designed and fabricated as the three-dimensional current collector for Zn metal anode. Abundant zincophilic sites on the surface of BaTiO3 induce zinc nucleation, enabling a compact and horizontally-aligned Zn morphology. At external electric field, the depolarization field produced the ferroelectric BaTiO3 layer on the electrode surface can accelerate the dissociation of ZnSO4 and regulate the Zn-ion desolvation process at the interfaces, leading to dendrite-free Zn deposition and less byproducts. As a result, the TiO2@BaTiO3/Zn anode achieves reversible Zn plating/stripping with low overpotential for over 3000 h at 3 mA cm−2 in symmetric cells, and the assembled full battery exhibits a significantly enhanced cycling stability over 1800 cycles at 1 A g−1. Ferroelectric nanotube arrays brings new opportunities for next-generation aqueous zinc-ion batteries.