A Comprehensive Strategy Enables High-Loading BiOBr@BiOIO₃ Cathodes for Quasi Ah-Level Aqueous Zn-Ion Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous zinc-ion batteries (AZIBs) are gaining attention for energy storage.
• High-loading cathodes are crucial for AZIBs' high energy density.
• Cycling stability of high-loading cathodes remains a significant challenge.

Purpose of the Study:

• To enhance the structural and mechanical stability of high-loading cathodes in AZIBs.
• To develop a sustainable and effective binder for high-loading cathode applications.
• To achieve high areal capacity in AZIBs through material and binder engineering.

Main Methods:

• Construction of BiOBr@BiOIO3 heterostructures via interfacial oxygen atom sharing.
• Design of a biomimetic binder through in situ dual cross-linking of guar gum and cation ions.
• Characterization using density functional theory (DFT) calculations and quantitative nanomechanics.

Main Results:

• The BiOBr@BiOIO3 heterostructure demonstrated enhanced reaction dynamics and structural stability.
• The biomimetic binder provided strong adhesion and robust mechanical properties to the cathode.
• An ultrahigh areal capacity of 20.02 mAh cm-2 was achieved with a loading of 100.71 mg cm-2.
• A quasi-ampere-hour level pouch cell (0.244 Ah) was successfully constructed.

Conclusions:

• The developed strategy effectively improves the stability and performance of high-loading cathodes in AZIBs.
• The BiOBr@BiOIO3 heterostructure and biomimetic binder show significant promise for practical AZIB applications.
• This work paves the way for high-energy-density and sustainable aqueous zinc-ion batteries.