Regulating Li₂S Deposition and Accelerating Conversion Kinetics through Intracavity ZnS toward Low-Temperature...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Uncontrolled lithium sulfide deposition and slow kinetics hinder lithium-sulfur (Li-S) battery performance, particularly at high sulfur loading and low temperatures.
• Developing advanced cathode hosts is crucial for overcoming these limitations and enabling practical Li-S battery applications.

Purpose of the Study:

• To design and synthesize a multifunctional sulfur (S) cathode host material for high-performance Li-S batteries.
• To investigate the role of ZnS nanoparticles confined in hollow porous carbon spheres (ZnS@HPCS) in regulating Li2S deposition and improving electrochemical kinetics.
• To elucidate the underlying mechanisms through experimental and theoretical analyses.

Main Methods:

• Synthesis of ZnS nanoparticles confined in hollow porous carbon spheres (ZnS@HPCS) using a capillary force-driven melting-diffusion strategy.
• Fabrication of Li-S battery cathodes using the synthesized ZnS@HPCS material.
• Electrochemical performance testing at room temperature and low temperature (-40 °C) under high sulfur loading (5.2 mg cm⁻²).
• In situ Raman spectroscopy and theoretical calculations to study Li2S nucleation and deposition mechanisms.

Main Results:

• The ZnS@HPCS cathode host effectively confined soluble polysulfides and solid Li2S, preventing uncontrolled deposition.
• The ZnS nanoparticles within the host trapped polysulfides, induced Li2S deposition, and accelerated conversion kinetics.
• Li-S batteries with ZnS@HPCS-S cathodes demonstrated excellent electrochemical performance, high reversible capacities, and stable cycling at both room and low temperatures.
• High sulfur loading (5.2 mg cm⁻²) was achieved with maintained performance.

Conclusions:

• The multifunctional ZnS@HPCS cathode host significantly enhances the electrochemical performance of Li-S batteries by addressing key challenges of Li2S deposition and conversion kinetics.
• The unique structure and composition of ZnS@HPCS provide fundamental insights into designing effective sulfur hosts for advanced energy storage systems.
• This approach offers a promising strategy for developing high-performance, low-temperature-operable Li-S batteries.