Zinc complex-based multifunctional binders for lithium sulfide-based lithium-sulfur batteries.

Area of Science:

• Materials Science
• Electrochemistry
• Battery Technology

Background:

• Lithium sulfide (Li2S) is a key cathode material for lithium-sulfur batteries (LSBs).
• Challenges include Li2S's moisture sensitivity and processing difficulties, necessitating suitable binders.
• Current binders like PVDF have limitations.

Purpose of the Study:

• To develop a novel fluorine-free binder for Li2S cathodes.
• To enhance the electrochemical performance and stability of Li2S-based LSBs.
• To investigate the role of binder properties in trapping lithium polysulfides (LPS) and catalyzing redox reactions.

Main Methods:

• Synthesis of a zinc acetate triethanolamine (Zn(OAc)2·TEA) complex binder.
• Incorporation of polyethylenimine (PEI) to form a hybrid Zn(OAc)2·TEA/PEI binder.
• Electrochemical testing of Li2S cathodes with the novel binder in LSBs.

Main Results:

• The Zn(OAc)2·TEA/PEI binder demonstrated superior specific capacity, rate capability, and cycling stability compared to PVDF.
• The binder effectively trapped lithium polysulfides (LPS) and exhibited redox catalytic activity.
• Li2S cathodes with 10 wt% PEI in the hybrid binder showed excellent rate performance and long-term cycling stability.

Conclusions:

• The Zn(OAc)2·TEA/PEI hybrid binder offers a promising fluorine-free solution for high-performance Li2S-based LSBs.
• The binder's ability to trap LPS and catalyze redox reactions is crucial for improved battery performance.
• This strategy advances the practical development of advanced LSB technology.