Multifunctional Cellulose Nanocrystals as a High-Efficient Polysulfide Stopper for Practical Li-S Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium-sulfur (Li-S) batteries face challenges in durability due to the polysulfide shuttle effect.
• Practical operation conditions like high sulfur content, loading, and temperature exacerbate performance degradation.

Purpose of the Study:

• To investigate the use of cellulose nanocrystals (CNCs) as a multifunctional polysulfide stopper for high-performance Li-S batteries.
• To address the limitations of current Li-S battery technology under demanding operational parameters.

Main Methods:

• Utilized low-cost, eco-friendly, hydrophilic cellulose nanocrystals (CNCs) as a cathode binder and separator coating.
• Employed Density Functional Theory (DFT) calculations to understand CNCs' interaction with polysulfides.
• Tested Li-S battery performance under high sulfur content (90 wt%), high loading (8.5 mg cm⁻²), and high temperature (60 °C).

Main Results:

• CNCs demonstrated strong binding affinity with polysulfides, confirmed by DFT calculations.
• CNCs effectively confined sulfur and polysulfides in the cathode and acted as a barrier against shuttling.
• The developed Li-S batteries exhibited outstanding cycling stability under challenging conditions.

Conclusions:

• Cellulose nanocrystals are a promising, cost-effective material for enhancing Li-S battery performance and durability.
• CNCs offer a multifunctional solution to mitigate polysulfide shuttling, enabling practical applications of Li-S batteries.