Synthesis and Sodium-Ion Storage of Triazole-Substituted Graphdiyne

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Sodium-ion batteries (SIBs) face challenges with low capacity and poor cycling stability in anode materials.
• Developing advanced anode materials is crucial for enhancing SIB performance.

Purpose of the Study:

• To design a novel anode material, triazole-substituted graphdiyne (TzlGDY), for SIBs.
• To investigate and elucidate a new diyne-radical sodium-ion storage mechanism.
• To enhance the capacity and cycling stability of SIB anodes.

Main Methods:

• Synthesis and characterization of triazole-substituted graphdiyne (TzlGDY).
• Electrochemical testing of TzlGDY as an anode material in SIBs.
• Investigation of the sodium-ion storage mechanism using theoretical and experimental approaches.

Main Results:

• TzlGDY exhibits a unique diyne-radical Na-storage mechanism involving Na+-N complexation and Na+-radical coupling.
• The TzlGDY anode demonstrates exceptional cycling stability with almost no capacity decay over 12,000 cycles at 5 A g-1, achieving 251.7 mAh g-1.
• A TzlGDY||NVP full cell delivered 114 mAh g-1 at 0.2C with 81.8% capacity retention after 150 cycles.

Conclusions:

• The discovered diyne-radical mechanism offers superior performance compared to existing cation-π mechanisms.
• TzlGDY's structure effectively stabilizes radicals and enhances ion transport, leading to high capacity and stability.
• This work introduces a new energy storage concept and a promising strategy for regulating anode materials in SIBs.