Phase Conversion Accelerating "Zn-Escape" Effect in ZnSe-CFs Heterostructure for High Performance Sodium-Ion...

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-ion batteries (SIBs) are promising for large-scale energy storage due to abundant sodium resources.
• Key challenges for SIBs include slow redox kinetics and poor capacity retention.
• Developing efficient anode materials is crucial for practical SIB applications.

Purpose of the Study:

• To develop a high-performance anode material for sodium-ion batteries.
• To enhance electron and Na+ transport efficiency in SIB anodes.
• To investigate the electrochemical behavior and mechanism of novel anode heterostructures.

Main Methods:

• Fabrication of ZnSe/carbon fiber (ZnSe-CFs) heterostructure anodes.
• In situ characterizations to study electrochemical behavior.
• Theoretical calculations to understand reaction mechanisms.
• Electrochemical testing of ZnSe-CFs in sodium-ion half and full batteries.

Main Results:

• The ZnSe-CFs anode exhibits high electron/Na+ transport efficiency.
• Phase conversion mechanism accelerates "Zn-escape" and forms a robust solid electrolyte interphase (SEI).
• Superior rate performance (206 mAh g-1 at 1500 mA g-1 in half-cell) and high initial capacity (197.4 mAh g-1 at 1 A g-1 in full-cell) were achieved.

Conclusions:

• Engineered ZnSe/C heterostructures provide a promising strategy for advanced SIB anodes.
• Understanding phase conversion mechanisms is key to optimizing anode performance.
• The developed ZnSe-CFs anode demonstrates significant potential for practical large-scale energy storage.