Nanochitin as Binder in Li-Ion Battery Anodes Enabling Aqueous Processing and Superior Solid Electrolyte Interphase

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Chemistry

Background:

• Binders are critical for battery electrode integrity and performance.
• Poly(vinylidene difluoride) (PVDF), a common binder, faces scrutiny due to its polyfluoroalkyl nature and reliance on organic solvents.
• Sustainable, fluorine-free binder alternatives are needed for eco-friendly battery manufacturing.

Purpose of the Study:

• To introduce chitin nanofibers (ChNFs) as a biobased, fluorine-free binder for battery electrodes.
• To investigate the mechanism of ChNF dispersion and stabilization of graphite.
• To evaluate the electrochemical performance of ChNF-based electrodes compared to PVDF.

Main Methods:

• Chitin nanofibers (ChNFs) derived from fisheries waste were used as a binder.
• Aqueous dispersion of graphite with ChNFs was achieved without surfactants.
• Colloidal probe microscopy, rheological analysis, and electrochemical testing were employed.
• Material characterization included electron microscopy and X-ray photoelectron spectroscopy.

Main Results:

• ChNFs effectively dispersed over 90% of graphite in water, forming stable suspensions.
• ChNF-graphite dispersions exhibited suitable rheological properties for electrode coating.
• Electrodes with 4% ChNFs showed high specific capacities and improved cycle stability over PVDF.
• ChNF binders resulted in a more robust solid electrolyte interphase (SEI), reducing electrolyte reduction.

Conclusions:

• Chitin nanofibers are a promising sustainable alternative to PVDF binders.
• Aqueous processing of battery electrodes is feasible using ChNFs.
• ChNF binders enhance electrochemical performance and electrode stability through improved SEI formation.