"Macro to micro" interface engineering-manipulated tin disulfide for stable and highly efficient sodium-ion...

Area of Science:

• Materials Science
• Electrochemistry
• Environmental Science

Background:

• Tin disulfide (SnS₂) is a promising material for sodium-ion capture but suffers from poor conductivity and volume changes.
• These limitations hinder its application in capacitive deionization (CDI) due to sluggish kinetics and performance decay.

Purpose of the Study:

• To address the limitations of SnS₂ for sodium-ion capture by developing a novel composite material.
• To enhance the electrochemical performance and stability of SnS₂-based electrodes for CDI applications.

Main Methods:

• Synthesis of hollow ZnS/SnS₂ microboxes embedded in sulfur-doped graphene (ZnS/SnS₂@SG) using interface engineering.
• Characterization of the material's structure, conductivity, and electrochemical properties.
• Evaluation of CDI performance, including desalination capacity, rate, and cyclic durability.
• Density functional theory (DFT) calculations to understand the mechanism of ion adsorption and electron transfer.

Main Results:

• The ZnS/SnS₂@SG composite exhibited a high desalination capacity of 109.7 mg_NaCl g^-1.
• An ultrafast time-average desalination rate of 10.1 mg_NaCl g^-1 min^-1 was achieved.
• The material demonstrated attractive cyclic durability, outperforming existing CDI electrodes.
• Interface engineering effectively alleviated volume expansion and lowered the Na⁺ diffusion energy barrier.

Conclusions:

• The developed ZnS/SnS₂@SG composite offers a superior solution for sodium-ion capture and CDI.
• Interface engineering is a viable strategy to enhance the electrochemical performance of materials for ion capture.
• This approach holds potential for developing next-generation electrochemical ion capture technologies.