A Highly Adhesive Binder Enables Sulfide-Based All-Solid-State Batteries with High Cycling Stability at Low Stack...

Area of Science:

• Materials Science
• Electrochemistry
• Chemical Engineering

Background:

• Sulfide-based all-solid-state lithium-ion batteries offer high energy density and safety.
• Electrode-electrolyte interface issues, like contact loss and reactions, cause capacity degradation, hindering commercialization.
• Developing stable and efficient interfaces is crucial for next-generation batteries.

Purpose of the Study:

• To enhance the electrode-electrolyte interface stability in sulfide-based all-solid-state lithium-ion batteries.
• To improve the adhesion and reduce interfacial resistance using a modified binder.
• To investigate the impact of the modified binder on battery performance and long-term cycling stability.

Main Methods:

• Modification of polystyrene-b-polybutadiene-b-polystyrene (SBS) binder with hydroxyl polar groups via click chemistry (SBS-Click).
• Fabrication of all-solid-state lithium-ion battery cells using the modified SBS-Click binder, commercial SBS binder, and HNBR binder.
• Electrochemical testing, including rate capability, cycling stability, and capacity retention measurements under various conditions (e.g., stack pressure, C-rates).

Main Results:

• The SBS-Click binder formed hydrogen bonds, improving adhesion between the cathode active material (LiNi_0.9Co_0.06Mn_0.04O₂@Li₃BO₃) and the sulfide electrolyte.
• SBS-Click cells showed superior rate performance and cycling stability compared to SBS and HNBR cells, especially under lower stack pressures.
• Cells with SBS-Click achieved high areal capacities (5.4 mAh cm^-2 at 0.1 C) and excellent capacity retention (83% after 6000 cycles at 3 C, stable operation >10,000 cycles at 5 C).

Conclusions:

• The hydroxyl-functionalized SBS-Click binder effectively mitigates electro-chemo-mechanical failures at the electrode-electrolyte interface.
• This approach significantly enhances the performance and durability of sulfide-based all-solid-state lithium-ion batteries.
• The findings accelerate the commercialization of safer and higher-energy-density solid-state batteries.