Bismuth Single Atoms Regulated Graphite Felt Electrode Boosting High Power Density Vanadium Flow Batteries

Area of Science:

• Electrochemistry
• Materials Science
• Energy Storage

Background:

• Vanadium flow batteries (VFBs) are promising for grid-scale energy storage.
• Low power density due to electrochemical polarization limits VFB performance.

Purpose of the Study:

• To develop a novel electrode material to enhance VFB power density and efficiency.
• To investigate the catalytic mechanism of single-atom bismuth in VFBs.

Main Methods:

• Fabrication of Bi single atoms supported by N-doped carbon-regulated graphite felt (Bi SAs/NC@GF).
• Electrochemical in situ characterization and theoretical calculations.
• Assembly and testing of VFB single cells and a 5 kW stack.

Main Results:

• Bi SAs/NC@GF exhibits high electrocatalytic activity and stability.
• Optimized Bi-N4 configuration enhances active sites and reduces polarization.
• VFB single cell achieved 81.1% energy efficiency at 240 mA cm⁻², compared to 70.5% for NC@GF.
• A 5 kW VFB stack operated stably for over 400 cycles.

Conclusions:

• Single-atom catalysts are effective for improving VFB performance.
• Bi SAs/NC@GF offers a scalable solution for high-power, low-cost VFBs.