한국전자기술연구원(KETI, 원장 신희동)이 전고체전지의 양극 내 활물질 함량 증가 시 발생하는 전극 특성 저하의 원인을 규명하고, 이를 해결하는 도전재 제어 기술을 개발했다.
Identifying the cause of electrode performance degradation when maximizing the content of positive electrode active material
The Korea Electronics Technology Institute (KETI, President Shin Hee-dong) has identified the cause of electrode performance degradation when the content of positive electrode active materials is maximized, thereby establishing a foundation for implementing high output of all-solid-state batteries.
KETI announced on the 17th that it has identified the cause of the deterioration of electrode characteristics that occurs when the content of active materials in the positive electrode of an all-solid-state battery increases, and developed a conductive material control technology to resolve this.
All-solid-state batteries are batteries that replace the liquid electrolyte that fills the space between the positive and negative electrodes of existing lithium-ion batteries with a solid electrolyte. They are recognized as a candidate for the next-generation secondary battery because they guarantee safety by eliminating the risk of explosion while also having a higher energy density than existing batteries.
In addition, since the solid electrolyte of the all-solid-state battery is composed of a mixture of materials such as positive electrode active material, conductive material, and binder within the electrode, there is an advantage of increasing the battery energy density if the content of the active material is maximized (the content of the solid electrolyte is minimized).
KETI Next-Generation Battery Research Center (Director Ji-Sang Yoo) precisely analyzed the cause of the decline in battery output and life characteristics that occurred when the content of positive electrode active materials in the electrode was increased to 90%, the world's highest level.
According to the research team led by Dr. Cho Woo-seok (Senior Researcher), when the content of active material in the electrode increases, the relative volume ratio of the solid electrolyte decreases, and in this case, the spherical carbon conductive particles distributed within the solid electrolyte region interfere with ion transfer and at the same time increase the contact area between the electrolyte and carbon, thereby causing oxidation. It caused a reaction.
In particular, the research team confirmed the mechanism by which the oxidation phenomenon of the solid electrolyte increased electrode resistance and ultimately caused deterioration of the battery.
To solve the above-mentioned battery performance degradation, the KETI research team applied a carbon conductive material with a controlled linear shape rather than a spherical shape, thereby successfully minimizing the contact area between the electrolyte and carbon and securing an effective path for ion conduction even when the active material content ratio is very high.
The results of this study were published in the latest issue (July 2024) of Advanced Functional Materials (IF=19.0), a world-renowned journal in the field of materials science.
Dr. Cho Woo-seok (Senior Researcher) and Dr. Kim Hyeon-seung (Senior Researcher), who led the technology development, said, “Through this research, we were able to confirm that it is possible to maximize the composition of active materials for a high-energy-density cathode.” They added, “We hope that this will be an opportunity to confirm how important it is to achieve an optimal combination of key materials within the electrode, and the research team will continue to contribute to the commercialization of all-solid-state batteries in Korea in the future.”