A Binder-Free Metal-Organic Framework Ion Osmosis Membrane for Stabilizing a Zn Anode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) offer a low-cost, safe alternative to conventional batteries.
• Key challenges include zinc dendrite formation and parasitic side reactions at the anode, limiting battery performance and lifespan.

Purpose of the Study:

• To develop a binder-free zirconium-based metal-organic framework (MOF) membrane, NUS-8, as an artificial solid electrolyte interphase (ASEI) for zinc anodes.
• To regulate Zn2+ desolvation and deposition, inhibit dendrite growth, and mitigate anodic side reactions in AZIBs.

Main Methods:

• Fabrication of a binder-free NUS-8 MOF membrane.
• Characterization of the NUS-8 membrane's structure and properties (microporous, functional groups).
• Electrochemical testing of symmetric Zn cells and Zn||MnO2 full cells with NUS-8 modified anodes.

Main Results:

• The NUS-8 membrane effectively controlled ion flux via an ion-confinement effect, reducing ion transfer resistance.
• NUS-8 enhanced anode surface hydrophilicity, accelerated Zn2+ desolvation, and lowered migration activation energy.
• Symmetric cells with NUS-8@Zn anodes achieved >1180 h lifespan, outperforming bare Zn anodes (90 h).
• Full cells demonstrated 72.3% capacity retention over 3000 cycles at 5 A g-1.

Conclusions:

• The NUS-8 MOF membrane serves as an effective ASEI, significantly improving Zn anode performance in AZIBs.
• This strategy offers a promising approach for advancing the stability and longevity of aqueous zinc-ion batteries.