Electrolytic Graphene Encapsulated CeO₂ for Lithium-Sulfur Battery Interlayer Separator

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Rare earth elements and graphene composites offer enhanced catalytic properties for energy storage.
• The polysulfide shuttle effect in lithium-sulfur batteries hinders performance and cycle life.
• Functional layers in separators can mitigate the shuttle effect.

Purpose of the Study:

• To prepare and evaluate cerium oxide/graphene composites (CeG) as a functional layer in battery separators.
• To investigate the effectiveness of CeG in suppressing the polysulfide shuttle effect.
• To assess the impact of CeG on the electrochemical performance and stability of energy storage cells.

Main Methods:

• Simultaneous intercalation exfoliation and in situ electrodeposition were used to synthesize CeO2/graphene composites.
• The structural properties of the CeG composite, including defect levels (ID/IG < 1), were characterized.
• Electrochemical performance was tested using separator cells with the CeG functional layer.

Main Results:

• The CeG composite exhibited a superior physical structure with low defect levels, effectively shielding polysulfides.
• The separator cell with CeG achieved a high initial discharge specific capacity of 1133.5 mAh/g at 0.5C.
• Excellent rate performance (978.5 mAh/g at 2C) and long cycling stability (790 mAh/g after 400 cycles) were demonstrated.

Conclusions:

• CeO2/graphene composites are effective in suppressing the polysulfide shuttle effect in energy storage devices.
• The unique structure of CeG enhances the cycling stability and rate capability of battery cells.
• This study highlights the potential of rare earth oxide-graphene composites for advanced energy storage materials.