Development of Korean 'Water Battery'... No Use of Japanese Materials

[Asia Economy Reporter Junho Hwang] Domestic researchers have developed a water-based secondary battery that is stronger and longer-lasting than existing lithium-ion batteries using Japanese materials.

KAIST announced on the 8th that a joint research team led by Professors Heetak Kim and Sangwook Kim developed a new water-based zinc-bromine battery. This battery is domestically produced without using expensive membrane materials or any additives, which were previously dependent on imports from Japan and other countries.

Preventing Japan's Dependence on Secondary Batteries

With the development of the water-based zinc-bromine battery, it is now possible to reduce external dependence on secondary battery technology. Recently, energy storage systems (ESS) that store electrical energy in advance and use it during needed times have gained attention to address the unstable power supply from renewable energy sources such as solar and wind power. However, lithium-ion batteries using separators or fluorine-based ion exchange membranes imported from Japan or the United States have been utilized as ESS.

Additionally, this battery's major strength is that it fundamentally eliminates the risk of fire, which is the biggest drawback of lithium-ion batteries. From 2017 to October of this year, a total of 21 fire accidents involving energy storage systems occurred. As a result, operation was suspended in 522 out of 1,490 ESS facilities, accounting for 35% of the total.

In particular, this battery is 45 times cheaper than lithium-ion batteries and can operate for over 1,000 cycles. It also has an energy efficiency equivalent to 83% of that of lithium-ion batteries.

Water-Based Battery Utilizing Nanotechnology

The research team opened the path to commercializing the water-based zinc-bromine battery by assigning the roles previously performed by membranes and additives to the battery's electrodes. They engineered the electrode surface with a microporous structure doped with nitrogen. Furthermore, by utilizing dipole-dipole interactions between nitrogen-doped carbon and polybromide, they fixed polybromide inside the pores. This enabled the development of a battery with high energy efficiency even without membranes.

Previously, development efforts were made on electrolyte additives that capture bromine and membranes that block bromine migration. However, it was difficult to solve issues such as increased costs and reduced output upon commercialization.

Professor Sangwook Kim stated, "We proposed a new solution using nanomaterial technology to overcome the limitations of next-generation water-based batteries." Professor Heetak Kim said, "We hope this research will accelerate the development of safer and more economical energy storage systems."

Doctoral candidate Juhyuk Lee and postdoctoral researcher Yerin Byun participated as co-first authors. This research was selected as the cover paper of the December 27, 2019 issue of the international journal Advanced Materials.

This research was conducted with support from the KAIST Institute for NanoCentury, the Energy Cloud Project Group, and the Creative Research Group for Multidimensional Nanoassembly Control, a leader researcher support project of the Ministry of Science and ICT.

This content was produced with the assistance of AI translation services.