An Adaptable Structure of Metal-Organic Framework Glass Interlayer Enables Superior Performance in Aqueous Zinc-Ion Batteries.

Abstract

The practical application of safe and cost-effective aqueous zinc-ion batteries is enhanced by the metal-organic frameworks (MOFs), which possess tunable porous structures and chemical compositions that can facilitate the desolvation and transport of Zn²⁺ ions at the anode interface. However, ensuring the structural stability and operational life of crystalline MOFs in batteries remains a challenge. Here, a breakthrough is presented in tackling this dilemma. A MOF glass interlayer, specifically the ZIF-62 glass interlayer, is designed and fabricated for the Zn anode. The integration of this interlayer endows the Zn anode with a remarkable cyclic lifespan. It also achieves outstanding cyclability in Zn||MnO₂ full-cell with limited Zn excess, showing no capacity decay after 600 cycles at 0.5 A g^-1, and in a Zn||iodine pouch battery with a mass loading of 12.85 mg cm^-2. This superior cyclicity is attributed to the ease of distortion of Zn[ligand]₄ tetrahedra and the reduced likelihood of disconnection between adjacent tetrahedra within the glass interlayer, as compared to its crystalline counterpart. The unique structure of ZIF-62 glass provides an increased degree of configurational freedom, allowing it to withstand mechanical stress and extend the Zn²⁺ ion diffusion pathway. This ensures high cycling stability and rapid interfacial diffusion kinetics.