AGM (Absorbent Glass Mat) Separator for Aqueous Zinc-Ion Battery, CAZIBAGMS

AGM (Absorbent Glass Mat) separators—composed of non-woven, micro-fiber borosilicate glass (typically 0.1–5.0 µm fiber diameter)—are the most widely used laboratory and baseline separators for aqueous zinc-ion batteries (AZIBs). Originally developed for lead-acid batteries, AGM has become the standard in zinc-ion research (e.g., in Zn/MnO2, Zn/ V2O5, and symmetric Zn/Zn cells) due to its high hydrophilicity, high electrolyte uptake, and low ionic transport resistance in aqueous sulfate or triflate salts (ZnSO4, Zn(OTf)2).

Its core advantages used in aqueous zinc-ion battery are: (1) Spontaneous Wetting & High Electrolyte Retention: Borosilicate glass surfaces feature abundant polar silanol (-Si-OH) groups, creating strong hydrogen bonding with water molecules. This ensures instantaneous electrolyte uptake and keeps the zinc metal anode thoroughly wetted throughout long cycling. (2) Low Interfacial & Bulk Impedance: High open porosity (>80%) and low tortuosity provide rapid Zn^{2+} ion diffusion pathways, enabling high-rate charge/discharge performance (>5-10 A/g) with minimal concentration polarization. (3) Chemical Stability in Mildly Acidic Media: Unlike alkaline zinc batteries (which can dissolve silica at pH > 13), mild aqueous electrolytes (pH 3.5-5.5) maintain the structural integrity of borosilicate glass over thousands of hours.

References: 

1. J. Zhi, et al. Biomolecule-guided cation regulation for dendrite-free metal anodes, Science Advances, 2020, 6, eabb1342.
2. W. Guo, et al., Separator Design for High-Performance Aqueous Zinc-Ion Batteries: Recent Advances and Future Outlooks, Small, 2026, 6, e202500466.