At the Korea Electrotechnology Research Institute (KERI), a team led by Dr. Dae-ho Kim and Jong-hwan Park of the Nano Convergence Research Center has developed a groundbreaking process technology to quickly manufacture the hard carbon cathode of a ‘sodium ion battery’ in 30 seconds using microwave induction heating technology, which is the principle of a microwave oven. It was announced on the 7th that it was developed.
Sodium ion batteries, one of the next-generation secondary batteries, replace the currently most widely used lithium (Li) with sodium (Na).
A team of Dr. Dae-ho Kim and Dr. Jong-hwan Park of the Korea Electrotechnology Research Institute developed a process technology to quickly manufacture ‘hard carbon’, the cathode material of sodium ion batteries, using ‘microwave induction heating technology’. Provided by Korea Electrotechnology Research Institute
Sodium, the main ingredient in salt, has reserves more than 1,000 times greater than lithium, and is easy to mine and smelt.
In addition, the reactivity of sodium is lower than that of lithium, so electrochemical stability inside the battery is high, it is advantageous for high-speed charging and discharging, and performance is maintained well even at low temperatures.
However, sodium-ion batteries have the disadvantage of having a very difficult manufacturing process, lower energy density and longer lifespan compared to lithium-ion batteries.
Since sodium ions have larger particles than lithium ions, hard carbon, which has a larger interlayer distance than graphite, the existing anode material, is used.
Hard carbon does not exist in nature and must be created artificially, but the process is very difficult.
Hard carbon can be made only by burning hydrocarbon materials, which are the main components of plants and polymers, at a temperature of over 1,000 degrees Celsius for a long time in an airless space.
The so-called ‘carbonization process’ is required, which poses an economic and environmental burden, which was one of the reasons preventing the commercialization of sodium ion batteries.
The team of Dr. Dae-ho Kim and Dr. Jong-hwan Park proposed a method of using rapid heating using ‘microwaves’, the principle of a microwave oven.
First, a film is made by mixing a small amount of carbon nanotubes, a new material that conducts electricity well, with polymer raw materials.
And when a microwave magnetic field is applied here, an induced current is generated in the carbon nanotubes, and only the film material is selectively heated to over 1,400 degrees in 30 seconds.
Through years of research, KERI already has technology to uniformly heat treat thin films made of conductive materials such as metals using microwave magnetic fields, and has received a lot of attention in industrial processes such as displays and semiconductors.
In addition, the institute’s Nano Convergence Research Center possesses the nation’s highest technology in the field of carbon nanomaterials.
The team of Dr. Dae-ho Kim and Dr. Jong-hwan Park used these capabilities to challenge the new field of sodium ion battery cathode materials and achieved good results.
The core technique is ‘Multiphysics Simulation’ developed by the research team. Through this, we were able to fundamentally understand the complex process that occurs when an electromagnetic field in the microwave band is applied to nanomaterials and create a new process method for manufacturing negative electrode materials for sodium ion batteries.
The related research results were highly evaluated, and a paper was recently published in ‘Chemical Engineering Journal (IF: 13.3, JCR top 3%)’, a world-class academic journal in the field of chemical engineering.
In publishing the paper, student researchers Gyeong-beom Ryu and Ji-won Shin, who had conducted an academic-research collaboration course at KERI, served as co-first authors.
The team of Dr. Dae-ho Kim and Dr. Jong-hwan Park said, “Sodium-ion batteries, which are safe and work well even in the cold winter, have received attention due to electric vehicle fire incidents, but the carbonization process for making cathode materials was greatly inferior in terms of energy efficiency and cost.” “’s microwave induction heating technology can produce hard carbon quickly and easily, which will greatly contribute to the commercialization of sodium ion batteries.”
In the future, the research team plans to continue efforts to improve the performance of cathode materials, and aims to develop technology that can continuously mass-produce large-area hard carbon films.
Next, we plan to expand the scope of use of the technology by determining that microwave induction heating can be used in fields such as all-solid-state batteries that require a high-temperature sintering process.
KERI, which has completed the domestic patent application, believes that this technology will receive a lot of attention from companies related to energy storage materials, and plans to promote technology transfer by discovering companies in demand.
Changwon = Reporter Kang Seung-woo ksw@segye.com
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2024-10-07 02:17:13