Next-Generation Ultrathin Lightweight Electrode for pH-Universal Aqueous Flow Batteries

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Aqueous flow batteries (AFBs) offer safe, scalable, long-duration energy storage.
• Current graphite felt (GF) electrodes are thick and heavy, limiting AFB power density.

Purpose of the Study:

• To develop a lightweight, ultrathin electrode for enhanced AFB performance.
• To evaluate the cost-effectiveness and efficiency of the novel electrode material.

Main Methods:

• A scalable one-step carbonization of cotton cloth to create carbon microtube electrodes (CME).
• Testing CME in acidic vanadium, neutral Zn-I2, and alkaline Zn-Fe flow batteries.
• Characterization of CME's conductivity, active sites, and electrolyte transport.

Main Results:

• CME is ultrathin (0.3 mm) and lightweight (50 g m⁻²), significantly reducing polarization.
• Achieved high power density (632.2 mW cm⁻²) in vanadium flow batteries.
• Demonstrated excellent cycling (750 cycles, 99.6% efficiency) in Zn-I2 batteries and high energy efficiency (>70%) in Zn-Fe batteries.
• CME is estimated to cost only 5% of GF electrodes.

Conclusions:

• The lightweight and ultrathin CME offers superior performance and cost benefits for AFBs.
• CME shows potential as a next-generation electrode material for various pH-universal AFBs.
• This innovation addresses key limitations in current flow battery electrode technology.