Mesoporous spatial separator rectified ion transport model for durable aqueous batteries

Abstract Zinc-based aqueous batteries (ZABs) are inherently safe and offer high capacity, yet the separator penetration by dendrite protrusion still plagues their wide-scale application due to the inherent uncontrolled Zn 2+ flux. Instead of conventional fibric separators with ion-surficial transport model, we introduce a spatial separator network via mono-micelle interface-confined assembly, featuring confined 3D nanofluidic channels that actively regulate Zn 2+ transport. Specifically, the spatial separator consists of hollow SiO 2 nanotubes (60–80 nm in diameter) interconnected by radially aligned 2.6 nm mesopores, i.e., a hierarchical mesopore@nanotube architecture. COMSOL simulations and in situ confocal laser scanning microscopy show that Zn 2+ ions preferentially migrate through the interconnected mesopore@nanotube spatial network, whereas SO 4 2− anions and solvent can be selectively confined. This hierarchical ions segregation facilitates a Zn 2+ -rich microenvironment ( ca. 2.6 M) and a localized electric field ( ca. 4 mV), concomitantly accelerating uniform Zn 0 nucleation. As a proof of concept, we first demonstrate a 40 cm-long flexible Zn//Br 2 fiber battery, enabling a high energy density of 49.9 Wh kg −1 and stable operation over 600 cycles, with loading of ca. 70 mg and capacity of 9 mAh. Our conceptual mesoporous spatial separator may accelerate the practical application of next-generation metal-based batteries by regulating ionic transport.