Novel Concept of Separator Design: Efficient Ions Transport Modulator Enabled by Dual‐Interface Engineering Toward Ultra‐Stable Zn Metal Anodes

Abstract Sluggish transport kinetics and rapid dendrite growth are considered the main obstacles that impair the performance of Zn metal batteries. This work has developed a unique strategy of dual‐interface engineering (DIE) to design the separator as efficient ions transport modulator. The dual function of spontaneous polarization effect and high zincophilicity of BaTiO 3 (BTO) is revealed by combining the theoretical and experimental studies. Benefiting from the decoration of BTO on glass fiber and well filling of the surface interspace, the DIE‐modified separator can not only effectively capture and accelerate Zn 2+ transport between the fiber–electrolyte interface, but also redistribute the ions transport into homogenization in the separator–anode interface. Therefore, the modified Zn anodes perform highly reversible Zn plating/stripping with ultrahigh cumulative capacity even up to 9500 mAh cm −2 at the high current density of 10 mA cm −2 . Meanwhile, the modified Zn‐MnO 2 battery can retain a specific capacity of 108 mAh g −1 after 1800 cycles at 1 A g −1 . Furthermore, the capacity retention of the battery also can be improved from 37.5% up to 115% at 0.2 A g −1 after 100 cycles. Such a novel concept for separator engineering provides a new perspective to enable ultra‐stable Zn metal anodes and high‐performance Zn metal batteries.