P-induced electronic modulation at the interface boosting p-d orbital coupling for high-performance vanadium flow...

Area of Science:

• Electrochemistry
• Materials Science
• Computational Chemistry

Background:

• Vanadium flow batteries (VFBs) are crucial for grid-scale energy storage, particularly for intermittent renewable sources.
• Sluggish V³⁺/V²⁺ redox kinetics at the negative electrode limit VFB high-rate performance.

Purpose of the Study:

• To investigate phosphorus (P) atom modulation of N, O dual-doped carbon interfaces for enhanced VFB performance.
• To develop a novel electrode material for high-rate and long-life VFBs.

Main Methods:

• Density functional theory (DFT) calculations to study electronic structure modifications.
• Fabrication of P-modulated polybenzimidazole (PBI)-derived N, O-rich composite electrodes via a loading-calcination strategy.

Main Results:

• DFT confirmed P atom modulation enhances vanadium ion adsorption and p-d orbital coupling.
• The modified electrode achieved 82.27% energy efficiency at 150 mA cm^-2.
• The VFB exhibited stable cycling with only 2.4% EE decay after 2000 cycles at 100 mA cm^-2.

Conclusions:

• Electronic structure modulation via P atom introduction is a viable strategy for improving VFB performance.
• This approach offers new insights for developing next-generation high-performance and long-life VFBs.