2D Electrides as Promising Anode Materials for Na-Ion Batteries from First-Principles Study

Area of Science:

• Materials Science
• Electrochemistry
• Computational Chemistry

Background:

• Rechargeable sodium-ion batteries (SIBs) are a promising alternative to lithium-ion batteries.
• Developing high-performance anode materials is crucial for advancing SIB technology.
• Current anode materials face challenges in capacity, stability, and ion diffusion.

Purpose of the Study:

• To investigate novel 2D nitrogen electride materials as potential anodes for SIBs.
• To evaluate the suitability of Ca2N as an anode material based on theoretical performance.
• To understand the fundamental properties governing the electrochemical behavior of Ca2N.

Main Methods:

• First-principles calculations were employed to predict material properties.
• Density Functional Theory (DFT) was used to model the electronic structure and ion diffusion.
• Calculations assessed Na atom absorption, electronic conductivity, Na migration barriers, and voltage profiles.

Main Results:

• A monolayer Ca2N sheet demonstrates a high theoretical specific capacity of 1138 mAh·g⁻¹.
• Pristine and Na-intercalated Ca2N exhibit metallic character, ensuring good electronic conductivity.
• Low Na migration energy barrier (0.084 eV) indicates fast room-temperature Na diffusion.
• Calculated average open-circuit voltages (0.18 V and 0.09 V) are beneficial for cell performance.
• Minimal lattice change upon Na intercalation suggests excellent cycling stability.

Conclusions:

• The 2D Ca2N monolayer shows exceptional potential as an anode material for SIBs.
• Its high capacity, rapid ion transport, and structural stability address key challenges in battery development.
• Ca2N represents a promising candidate for next-generation high-performance rechargeable batteries.