A technology to enhance the durability of aqueous zinc batteries has been developed domestically.
On the 17th, the Korea Institute of Energy Research announced that the research team led by Dr. Yang Jeong-hoon and Dr. Lee Chan-woo from the Energy Storage Research Group developed a new electrode material based on copper oxide and applied it to aqueous zinc batteries, successfully increasing their durability by three times.
(From left) Dr. Yang Jeonghun, Researcher Park Sanghyun, Dr. Lee Chanwoo. Provided by Korea Institute of Energy Research
Aqueous zinc batteries are secondary batteries that use water as the electrolyte. Compared to lithium-ion batteries that use volatile liquid electrolytes, they have the advantages of lower fire risk and being environmentally friendly. Above all, their manufacturing and material costs are low, making them a promising next-generation energy storage system (ESS).
However, a drawback is their short lifespan due to the dendrite phenomenon, where zinc metal deposits elongate on the anode surface during charging. Dendrites refer to the irregular, branch-like growth of metal ions deposited disorderly on the anode during the battery charging process. This irregular growth can cause short circuits, severely impacting battery stability and shortening its lifespan.
The research team suppressed dendrite formation in aqueous zinc batteries using an "electron sponge" technology that effectively absorbs and releases electrons at the anode. The aqueous zinc batteries applied with this technology demonstrated three times higher durability compared to conventional batteries.
Previously, the team tested candidate materials with zinc alloy characteristics by particle size. As a result, they discovered that copper oxide nanoparticles exhibited the best zinc affinity, leading to the development of copper oxide nanoparticles applied to aqueous zinc batteries.
In zinc batteries, electrons at the anode meet zinc ions to form zinc metal, storing electricity. At this time, copper oxide nanoparticles absorb electrons like a sponge absorbs water, allowing zinc to adhere evenly. This even formation of zinc suppresses dendrites caused by irregular zinc growth.
Additionally, during discharge, the sponge-like nanoparticles quickly release electrons like squeezing water from a sponge, promoting the dissolution of zinc metal and minimizing residual zinc on the anode surface. According to the research team, this prevents residual zinc from growing into dendrites during repeated charge-discharge cycles.
The research team named this technology "electron sponge" and demonstrated through computational science that it can also reduce energy loss used in battery charging.
When applied to aqueous zinc batteries, specifically zinc-polyiodide flow batteries, no dendrites formed even after about 2,500 charge-discharge cycles. Considering that conventional batteries fail due to dendrite formation after about 800 cycles, this means the durability is more than three times higher.
In particular, the ratio of discharge capacity to charge capacity was measured at 98.7%, showing high efficiency characteristics. Furthermore, it succeeded in achieving a high energy density of 180 Wh/L, which is more than 30% higher than previously reported zinc-polyiodide flow batteries, significantly enhancing commercialization potential.
Dr. Yang Jeong-hoon and Dr. Lee Chan-woo stated, "We expect this research result to provide an important clue for the development of next-generation zinc batteries," and added, "The research team plans to rapidly verify performance at a commercial scale by integrating the newly developed copper oxide electrode material with a 3.5 kW-class zinc-polyiodide flow battery demonstration technology."
Meanwhile, this research was conducted with support from the Korea Institute of Energy Research’s basic project and Samsung Future Technology Development Project.
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