An accumulator that lasts 27 years and costs less

In a significant advance in energy storage technology, researchers have developed a new electrode that effectively suppresses the harmful phenomenon of self-discharge in flow-free zinc-bromine (FLZBB) batteries, meaning they can retain a charge even when not in use.

The search for clean, sustainable energy is ongoing, and researchers are constantly innovating to improve energy storage systems. Lithium-ion batteries, while dominant, have a major safety issue: flammable electrolytes.

FLZBBs offer a promising alternative due to their combustible properties and use of popular metals. However, a nagging problem known as self-emission has hindered their widespread adoption. The study was published that day Journal of Chemical Engineering.

Now, a team of researchers from the Gwangju Institute of Science and Technology (GIST) in Korea has developed a revolutionary electrode that solves this problem, paving the way for a future powered by safe and efficient FLZBBs.

Making FLZBBs useful

FLZBBs boast several advantages over lithium-ion batteries. They are safe, cheap and simple in design. They work with a positive electrode, a negative electrode, a separator to keep them apart, and a gel-like electrolyte.

However, during operation, bromine ions generated at the positive electrode migrate to the negative electrode, causing self-discharge and inhibiting performance. This was a major obstacle for FLZBB.

Professor Sanho Park and his team, including the study's first author Youngin Cho, have developed an innovative electrode that effectively puts an end to self-discharge. It is a thick graphite field electrode coated with nitrogen-doped mesoporous carbon (NMC/GF).

Their work paves the way for more stable and efficient FLZBBs. Here is their chemical activity

Trapping ions: How the NMC/GF electrode works

The NMC/GF electrode is fabricated in a simple and economical manner. The researchers coated a standard graphite wool electrode with the precursor material, followed by drying and polymerization. The magic lies in the mesopores (tiny pores) created by the NMC coating.

These mesopores, with strategically placed nitrogen sites, act as small cages, trapping bromine ions and their complexes inside the positive electrode. This prevents it from reaching the negative electrode, stopping self-discharge.

“This coating makes the original hydrophobic GF electrodes ultrahydrophilic, improves the interfacial contact with the electrolyte in the aqueous electrolyte, and increases the electrochemical performance,” explains Prof Bach on the advantages of the NMC/GF electrode.

“Additionally, it allowed for the incorporation of abundant oxygen and nitrogen species, which improved the reaction rate of the bromine, increasing efficiency.”

Unprecedented performance and longevity

The FLZBBs with the NMC/GF electrode showed exceptional performance, with a Coulomb efficiency of 96% and an energy efficiency of 76% at a given current density. They also presented a high surface capacity (amount of charge stored per unit area) of 2 mAh cm-2. But that's not all.

These batteries have demonstrated remarkable durability lasting for more than 10,000 charge and discharge cycles – a testament to their long-term sustainability. This represents a satisfactory life cycle of 27 years.

Additionally, using a thicker GF electrode can reduce battery costs.

In Press releasea, Bach, excited about the future implications: “The development of the FLZBB positive electrode, which maintains long-term operation over 10,000 cycles with high efficiency, will accelerate the development of sustainable ESSs and the long-term green energy transition. Also, the NMC/GF positive electrode can also be used for other hydroelectric batteries. can be used.

This innovation has the potential to revolutionize the world of energy storage. With safer, more sustainable and durable FLZBBs on the horizon, the path to a clean and sustainable energy future looks a little brighter.