Ternary Heterostructures With Gradient Built-In Electric Fields Through Stepwise Screening for Highly Reversible...

Area of Science:

• Materials Science
• Electrochemistry
• Computational Materials Science

Background:

• Sodium-ion batteries require improved low-temperature performance.
• Traditional heterostructures face limitations in efficiency and interface control for sodium storage.

Purpose of the Study:

• To develop a screening-driven strategy for designing heterostructures for low-temperature sodium storage.
• To understand the relationship between heterostructure properties and electrochemical performance.
• To create advanced ternary heterostructures for enhanced sodium storage.

Main Methods:

• Computational screening using theoretical descriptors.
• Fabrication of MoS₂/MoO₂ and MoS₂/MoO₂/Ti₃C₂Tₓ heterostructures.
• Electrochemical performance testing at low temperatures (-20°C).

Main Results:

• MoS₂/MoO₂ identified as an optimal binary heterostructure.
• Work function difference and charge redistribution are key factors in Na⁺ storage.
• Ternary MoS₂/MoO₂/Ti₃C₂Tₓ heterostructure with cascaded work function alignment and gradient electric field demonstrated.
• Achieved high reversible capacity, excellent rate performance, and robust cycling stability at -20°C.

Conclusions:

• A general and predictive strategy for designing high-performance electrodes was established.
• Ternary heterostructures with multi-interface systems offer significant advantages for low-temperature sodium storage.
• The work function alignment and resulting electric field are crucial for efficient sodium ion storage and transport.