Highly branched amylopectin binder for sulfur cathodes with enhanced performance and longevity

Area of Science:

• Materials Science
• Electrochemistry
• Sustainable Energy

Background:

• Lithium-sulfur (Li-S) batteries face challenges with sulfur cathode mechanical instability and polysulfide dissolution.
• Traditional binders like PVDF offer limited performance and environmental drawbacks.

Purpose of the Study:

• To develop a low-cost, non-toxic, and environmentally benign aqueous binder for Li-S battery sulfur cathodes.
• To investigate the efficacy of highly branched amylopectin (HBA) as a binder, inspired by natural adhesives.

Main Methods:

• Extraction of highly branched amylopectin (HBA) from natural sources.
• Fabrication of Li-S battery cells using HBA as a cathode binder.
• Electrochemical performance testing and cycling stability analysis compared to traditional binders.

Main Results:

• HBA-based Li-S cells demonstrated superior electrochemical performance over those using PVDF or lowly branched polysaccharides.
• The HBA binder enhanced cathode mechanical strength and ionic conductivity, maintaining framework integrity during cycling.
• HBA exhibited improved polysulfide retention via hydroxyl groups and C-S bond formation, suppressing the shuttle effect.

Conclusions:

• Highly branched amylopectin (HBA) is a highly effective and sustainable binder for lithium-sulfur battery cathodes.
• HBA enables long cycle life (500 cycles at 2C) with minimal capacity fading (0.104% per cycle) due to enhanced mechanical properties and polysulfide trapping.
• This bio-inspired approach offers a promising pathway for developing advanced and eco-friendly energy storage solutions.