Functionalizing Janus-structured Ti₂B₂ unveils exceptional capacity and performance in lithium-ion battery anodes

Area of Science:

• Materials Science
• Electrochemistry
• Nanotechnology

Background:

• Lithium-ion batteries (LIBs) are crucial for energy storage, driving demand for advanced anode materials.
• Two-dimensional MBenes, like Ti2B2, show promise for LIB anodes but suffer from limited lithium storage capacity.
• Surface functionalization is explored to overcome limitations in MBenes for enhanced LIB performance.

Purpose of the Study:

• To investigate the potential of functionalized Janus-structured MBenes (Ti2B2XaXb) as high-performance anode materials for LIBs.
• To explore the impact of different surface functional groups (N, O, S, Se) on the electrochemical properties of Ti2B2.
• To understand the atomic-scale mechanisms governing lithium storage in functionalized MBenes.

Main Methods:

• First-principles simulations based on density functional theory (DFT) were employed.
• Geometric characteristics and electrochemical properties of Ti2B2XaXb were systematically investigated.
• Theoretical specific capacity, ion diffusion barriers, and open-circuit voltage were calculated.

Main Results:

• Ti2B2NO demonstrated a high theoretical specific capacity of 1091.17 mAh·g−1, a 2.4-fold increase over pristine Ti2B2.
• Low lithium diffusion barrier (0.33 eV) on the O-terminated side of Ti2B2NO facilitates rapid charging/discharging.
• Ti2B2NO operates within a safe voltage range (0-1 V), ensuring battery operational safety.

Conclusions:

• Surface functionalization of Janus-structured MBenes, particularly with Ti2B2NO, significantly boosts lithium storage capacity.
• The low diffusion barrier and safe operating voltage of Ti2B2NO make it a promising candidate for next-generation LIB anodes.
• This research provides fundamental insights into tailoring MBenes for advanced energy storage applications.