A Long-Life and Excellent Rate-Capability Aqueous Zn-Benzoquinone Battery Enabled by Iodine-Catalyzed Cathode

Area of Science:

• Materials Science
• Electrochemistry
• Energy Storage

Background:

• Benzoquinone (BQ) is a promising cathode material for aqueous zinc batteries.
• BQ electrodes suffer from sublimation and poor conductivity, limiting performance and causing mass loss.
• Developing stable and efficient organic cathode materials is crucial for advanced batteries.

Purpose of the Study:

• To enhance the performance of benzoquinone (BQ) cathode materials in aqueous zinc-based batteries.
• To address the limitations of sublimation and poor electrical conductivity in BQ electrodes.
• To investigate the catalytic effect of iodine (I2) species on the BQ/BQ2- couple.

Main Methods:

• Utilizing N-doped porous carbon (NPC) as a host material for anchoring BQ molecules.
• Incorporating iodine (I2) species as an efficient catalyst in the BQ cathode.
• Fabricating a combined electrode denoted as BQ-I@NPC with 1wt% I2 additive.
• Evaluating electrochemical performance, including specific capacity, energy density, and cycling stability.

Main Results:

• The BQ-I@NPC cathode achieved a high specific capacity of approximately 482 mAh g-1 at 0.25 A g-1.
• A high energy density of 545 Wh kg-1 (based on BQ) was realized, representing the highest among reported organic cathode materials for aqueous Zn-based batteries.
• The electrode demonstrated superior cycling stability, retaining approximately 80% capacity after 20,000 cycles at 10 C.
• Iodine (I2) acted as a carrier, accelerating Zn2+ transmission and reducing voltage hysteresis.

Conclusions:

• Iodine (I2) catalysis effectively promotes the reversible conversion of the BQ/BQ2- couple in Zn-BQ batteries.
• N-doped porous carbon serves as an excellent host for anchoring BQ, mitigating sublimation and improving conductivity.
• The developed BQ-I@NPC cathode offers a viable strategy for high-performance organic electrodes in aqueous zinc batteries.
• This approach provides an effective pathway towards developing advanced, high-energy-density organic cathode materials.