Multifunctional SnO₂ QDs/MXene Heterostructures as Laminar Interlayers for Improved Polysulfide Conversion and...

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium-sulfur (Li-S) batteries suffer from poor cycling stability due to lithium polysulfide (LiPS) shuttling.
• Advanced electrode/electrolyte design and interlayer architectures are crucial for improving Li-S battery performance.

Purpose of the Study:

• To develop an ultrathin and laminar SnO2@MXene heterostructure interlayer for Li-S batteries.
• To investigate the role of heterogeneous catalysis in inhibiting LiPS shuttling and improving redox kinetics.

Main Methods:

• Fabrication of an ultrathin SnO2@MXene heterostructure interlayer with uniformly distributed SnO2 quantum dots on a MXene layer.
• Electrochemical testing of Li-S cells with the modified separator, including cycling stability and coulombic efficiency measurements.
• Analysis of lithium deposition behavior during cycling.

Main Results:

• The SnO2@MXene interlayer effectively suppressed LiPS shuttling and promoted homogeneous Li deposition.
• Li-S cells with the SnO2@MXene interlayer exhibited superior electrochemical performance compared to cells with a bare separator.
• An areal capacity of 7.6 mAh cm-2 at a high sulfur loading of 7.5 mg cm-2 and stability over 500 cycles were achieved.

Conclusions:

• The laminar SnO2@MXene separator interlayer is a feasible strategy for advancing Li-S battery commercialization.
• Heterostructure catalysis with enhanced reaction kinetics is key to improving Li-S battery performance.
• The study provides insights into the design of advanced interlayers for high-performance energy storage devices.