Sodium Alginate Binders for Bivalency Aqueous Batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Green Chemistry

Background:

• Sodium alginate (SA) is water-soluble, limiting its use as a binder in aqueous batteries.
• Polyvinylidene difluoride (PVDF) is a common binder but requires toxic N-methyl-2-pyrrolidone (NMP) solvent.
• Developing eco-friendly and efficient binders is crucial for sustainable battery technology.

Purpose of the Study:

• To investigate the use of sodium alginate (SA) as a binder in aqueous batteries.
• To overcome the solubility issue of SA by cross-linking it with Zn2+ ions.
• To evaluate the performance of SA-based binders compared to traditional PVDF binders.

Main Methods:

• Synthesizing a water-insoluble SA binder through cross-linking with Zn2+ ions.
• Fabricating LiFePO4 cathodes using the novel SA binder and conventional PVDF binder.
• Assembling and testing aqueous Zn||LiFePO4 battery cells under various conditions.

Main Results:

• The cross-linked Zn-SA binder exhibited excellent water insolubility and mechanical strength.
• LiFePO4 cathodes with the SA binder showed superior capacity retention (93.7%) over 100 cycles compared to PVDF (84.7%).
• SA-based electrodes demonstrated improved properties, including reduced redox polarization and enhanced ion diffusion.

Conclusions:

• Sodium alginate can be effectively utilized as an eco-friendly binder in aqueous batteries via Zn2+ cross-linking.
• The developed Zn-SA binder offers a sustainable alternative to PVDF, eliminating the need for toxic organic solvents.
• This advancement significantly enhances the electrochemical performance and durability of aqueous Zn batteries.