In an exciting breakthrough for safer and more durable energy storage, researchers in South Korea have developed a new technology called the “electron sponge” that could dramatically improve the lifespan of aqueous zinc-ion batteries.
Their work, led by Dr. Jung Hoon Yang and Dr. Chan-Woo Lee at the Korea Institute of Energy Research, was recently published in the journal Nature Communications.
Aqueous zinc-ion batteries use water as their electrolyte, making them much safer than traditional lithium-ion batteries, which rely on flammable liquids and carry a risk of fires.
Zinc batteries are also cheaper to make and better for the environment, so scientists have long hoped they could become a leading option for next-generation energy storage systems.
However, one major problem has held them back: during charging, tiny metal spikes called dendrites can grow on the battery’s zinc surface. These dendrites can eventually pierce the internal layers of the battery, causing short circuits and drastically shortening the battery’s life.
To solve this issue, the research team developed tiny copper oxide nanoparticles that act like an “electron sponge” inside the battery.
These particles absorb and release electrons efficiently at the anode—the battery’s negative side—helping to guide the zinc ions to deposit smoothly and evenly instead of forming dangerous dendrites.
In simple terms, when the battery charges, the copper oxide nanoparticles quickly soak up electrons, like a sponge absorbs water, helping zinc to coat the surface evenly. When the battery discharges, the “sponge” squeezes out the electrons, allowing the zinc to dissolve smoothly without leaving behind dangerous leftovers that could grow into dendrites over time.
Through experiments and computer modeling, the researchers showed that this method not only prevents dendrites but also reduces energy loss during charging.
When they tested the electron sponge in a type of zinc battery called a zinc–polyiodide flow battery, it completed over 2,500 charging cycles without any sign of dendrite growth. In comparison, regular batteries typically start to fail after around 800 cycles, showing that this new technology makes batteries more than three times as durable.
The improved battery also performed extremely well, with a high efficiency of 98.7% between charging and discharging.
It achieved an energy density of 180 watt-hours per liter—over 30% better than earlier zinc–polyiodide flow batteries—making it a strong candidate for future large-scale energy storage solutions.
Dr. Yang and Dr. Lee said they hope this breakthrough will lead to the next generation of safer, high-performance zinc batteries. They are now moving forward to test the new copper oxide electrode material in a larger, real-world 3.5-kilowatt battery demonstration system.
