Expediting ion migration and stabilizing interface deposition through pre-polarized ion channels for zinc-ion batteries

Abstract

Irregular deposition and sluggish reduction kinetics of zinc ions (Zn²⁺) are major causes of dendrite growth, which significantly shortens the lifespan of zinc-ion batteries. Locally promoting Zn²⁺ transport and directing Zn deposition are expected to circumvent the above challenges. Herein, the concept of pre-polarized Zn²⁺ channels is proposed to accelerate the kinetics of Zn²⁺ and promote uniform Zn deposition. As a proof-of-concept material, barium titanate (BaTiO₃) is utilized to exert polarization effects (the Maxwell–Wagner effect), which stem from the re-orientation of the BaTiO₃ static electrical domain by applying an external electrical field. The polarized BaTiO₃ porous nanofibers generate an orientational static electric field to form pre-polarized channels that homogenize Zn²⁺ distribution at the electrode/electrolyte interface, thus facilitating flat zinc metal deposition. This design endows the cell with stable Zn plating/stripping for 2800 hours at a current density of 1 mA cm⁻² and areal capacity of 0.5 mA h cm⁻². Full Zn//MnO₂ cells equipped with pre-polarized channels maintain a specific capacity of 77 mA h g⁻¹ after 3500 cycles at a current density of 5 A g⁻¹. This research advances material design by polarizing the electric field to regulate Zn²⁺ channels.