Suppression of Vanadium Oxide Dissolution via Cation Metathesis within a Coordination Supramolecular Network for Durable Aqueous Zn-V2O5 Batteries

Aqueous zinc metal batteries (ZMBs) are a promising sustainable technology for large-scale energy storage applications. However, the water is often associated with problematic parasitic reactions on both anode and cathode, leading to the low durability and reliability of ZMBs. Here, a multifunctional separator for the Zn-V2O5 batteries by growing the coordination supramolecular network (CSN:Zn-MBA, MBA = 2-mercaptobenzoic acid) on the conventional non-woven fabrics (NWF) is developed. CSN tends to form a stronger coordination bond as a softer cation, enabling a thermodynamically preferred Zn2+ to VO2+ substitution in the network, leading to the formation of VO2-MBA interface, that strongly obstructs the VO2(OH)(2)(-) penetration but simultaneously allows Zn2+ transfer. Moreover, Zn-MBA molecules can adsorb the OTF- and distribute the interfacial Zn2+ homogeneous, which facilitate a dendrite-free Zn deposition. The Zn-V2O5 cells with Zn-MBA@NWF separator realize high capacity of 567 mAh g(-1) at 0.2 A g(-1), and excellent cyclability over 2000 cycles with capacity retention of 82.2% at 5 A g(-1). This work combines the original advantages of the template and new function of metals via cation metathesis within a CSN, provides a new strategy for inhibiting vanadium oxide dissolution.

Automated summary

A multifunctional separator for Zn-V2O5 batteries is developed by growing a coordination supramolecular network (CSN:Zn-MBA) on non-woven fabrics. This separator allows for Zn2+ transfer while inhibiting VO2(OH)(2)(-) penetration, leading to dendrite-free Zn deposition. The Zn-V2O5 cells with this separator exhibit high capacity and excellent cyclability.