Ion-Sieving Dual-Scale Asymmetric Cellulose Membrane as a Sustainable Paper-Based Separator for Ultra-Stable Zinc...

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Conventional separators in aqueous zinc-ion batteries (ZIBs) fail to prevent zinc dendrite growth and parasitic reactions due to poor ion transport control.
• This leads to limited battery lifespan and performance.

Purpose of the Study:

• To design and evaluate a fully biodegradable, dual-scale asymmetric paper-based membrane for enhanced ion regulation in ZIBs.
• To suppress zinc dendrite formation and mitigate parasitic reactions for improved battery stability and longevity.

Main Methods:

• Fabrication of a dual-scale membrane coupling a macroporous paper scaffold with carboxylated nanoporous cellulose nanofibers (CNFs).
• Investigation of ion transport mechanisms, including coordination-assisted ion-hopping via Zn²⁺-COOH interactions.
• Electrochemical testing of the membrane as a separator in Zn||Zn symmetric cells and Zn||Cu cells, and in Zn||I₂ full cells.

Main Results:

• The membrane facilitated uniform Zn²⁺ flux, inhibiting dendrite growth and enabling stable cycling over 1,900 h in Zn||Zn cells.
• Achieved a sixfold lifespan extension compared to glass fiber separators in Zn||Cu cells with 97.3% average Coulombic efficiency.
• Demonstrated excellent performance in Zn||I₂ cells, retaining capacity after 4,000 cycles and suppressing shuttle effects.

Conclusions:

• The developed cellulose-based membrane offers effective ion regulation, suppressing dendrites and side reactions in ZIBs.
• This sustainable design significantly enhances battery lifespan and reduces separator costs by 83%.
• Presents a practical and eco-friendly pathway for developing high-performance aqueous ZIBs.