KIST, Investigation of Performance Deterioration Due to Rapid Battery Charge and Discharge
Establishment of a platform for analyzing the performance degradation mechanism of electrode materials
Also laying the foundation for designing next-generation battery materials for electric vehicles


As electric vehicles become more widespread, attention is being paid to the performance and lifespan of lithium-ion batteries, which are the power source. Unlike existing small lithium-ion batteries, electric vehicle lithium-ion batteries must be able to be used without problems even in situations that require high output, such as rapid acceleration.

A joint research team led by Dr. Won-Young Jang of the Energy Storage Research Group at the Korea Institute of Science and Technology (KIST) and Dr. Seung-Min Kim of the Carbon Fusion Materials Research Center at the Jeonbuk Branch announced on the 3rd that they have built a platform that can elucidate the extent of deformation of electrode materials and deterioration of electrochemical performance when lithium-ion batteries for electric vehicles are used rapidly.

When lithium-ion batteries are used at high power, the batteries discharge rapidly. Under such rapid charging and discharging conditions, a problem occurs in which the battery capacity is reduced significantly compared to that obtained during slow charging and discharging.

This repetition of high-power charging and discharging ultimately reduced the lifespan of lithium-ion batteries, making it difficult to expand the electric vehicle market.

In a previous study, Dr. Jang Won-young's research team at KIST built a platform that can analyze the performance degradation of lithium-ion batteries that occurs when rapidly charging them by analyzing ternary (Ni, Co, Mn) cathode (+) materials.

This time, we analyzed a different cathode material, 'high-nickel material (NCA),' to elucidate the performance degradation that occurs when the battery is rapidly discharged due to excessive use.

The research team analyzed deformation of electrode materials that can cause operational errors and safety accidents in various driving environments of electric vehicles, such as rapid charging and discharging of lithium-ion batteries.

Through this, it was revealed that rapid discharge phenomena such as rapid acceleration limit the amount of lithium ions transferred to the positive electrode, and that the internal deformation of the incompletely recovered electrode material is ultimately a factor in the reduction of battery capacity and shortened lifespan. />
It was also confirmed that the instability of the electrode structure increases further when charging and discharging at high voltage for high-capacity use.

The research team established a performance degradation analysis platform for battery materials that can check at a glance the subtle initial changes occurring in the internal structure of the electrode that lead to performance degradation over a wide range, and clarified the performance degradation mechanism of battery materials.

Dr. Jang Won-young said, “Through this research, we have discovered the mechanism of battery performance degradation due to irregular internal deformation of battery materials during rapid acceleration of electric vehicles,” and “Based on this, we will develop stable battery materials that do not have battery performance issues during rapid acceleration in the future.”

Meanwhile, this study was conducted with support from the Ministry of Science and ICT as a major project of KIST and as a mid-career researcher support project of the National Research Foundation of Korea, and the results of the study are scheduled to be published as a cover paper in the latest issue of 'Angewandte Chemi', an international academic journal in the field of chemistry.