Functional-Group-Engineered Cellulose Separators for Aqueous Zinc-Ion Batteries: Structural Design and Interfacial...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) offer safe, low-cost, and eco-friendly large-scale energy storage.
• Challenges in AZIBs include zinc anode dendrite growth, hydrogen evolution, corrosion, and interfacial side reactions, limiting cycling stability.
• Separators are evolving from passive barriers to active components regulating ion transport and interfacial chemistry.

Purpose of the Study:

• To review functional-group-engineered cellulose separators for aqueous zinc-ion batteries.
• To highlight structural features, advantages, and limitations of modified cellulose separators.
• To discuss interfacial regulation mechanisms for enhanced battery performance.

Main Methods:

• Focus on hydroxyl-rich, carboxylated, sulfonated, and amino-functionalized cellulose separators.
• Analysis of interfacial regulation mechanisms: Zn²⁺ coordination, flux homogenization, anion exclusion, water-activity control, and side-reaction suppression.
• Review of structural features and modification strategies for cellulose-based separators.

Main Results:

• Functionalized cellulose separators effectively regulate Zn²⁺ transport and suppress detrimental interfacial reactions.
• Specific functional groups (carboxyl, sulfonate, amino) impart distinct advantages in controlling ion flux and water state.
• Engineered cellulose separators demonstrate potential for significantly improving the cycling stability of AZIBs.

Conclusions:

• Cellulose separators, through functionalization, are crucial for overcoming AZIB anode instability.
• Precise functional-group design and understanding interfacial mechanisms are key to developing high-performance separators.
• Future research should focus on scalable fabrication and standardized device-level evaluation for practical applications.