**Schematic Diagram of Fast-Charging Lithium-Ion Battery Solvent**
With the growth of the electric vehicle (EV) market, technology to reduce lithium-ion battery charging time has emerged as a crucial task. Researchers at the Korea Advanced Institute of Science and Technology (KAIST) have developed an innovative electrolyte technology that reduces the charging time to 15 minutes.
KAIST announced on the 17th that the team led by Professor Nam-Soon Choi from the Department of Life Chemistry, in collaboration with Professor Seung-Beom Hong’s team from the Department of Materials Science and Engineering, developed a new electrolyte solvent called ‘isobutyronitrile (isoBN).’ This strategy maximizes lithium-ion movement within the battery, achieving this result.
The research team devised a strategy to control the solvation structure within the electrolyte. This optimizes the formation of the anode interface layer (SEI), a key component of batteries, facilitating the smooth movement of lithium ions and addressing issues like battery lifespan reduction during fast charging, thereby improving the charging speed of lithium-ion batteries.
The traditional electrolyte used for lithium-ion batteries, which includes ethylene carbonate (EC), has high viscosity and strong solvation characteristics. These properties create an anode interface layer composed of large crystallites, which hinders the smooth movement of lithium ions during fast charging and prevents them from entering the graphite anode’s layered structure.
Additionally, metallic lithium deposits on the anode interface layer or the top of the anode plate, increasing the risk of battery lifespan reduction and fire due to short circuits.
To counter this, the research team introduced isoBN into the battery electrolyte, completely replacing EC. This reduced lithium-ion desolvation energy and decreased the crystallite size of the anode interface layer.
The introduction of isoBN solvent led to the development of a high-ion conductive electrolyte system with 55% lower viscosity and 54% higher ionic conductivity (12.80 S/cm) compared to the EC electrolyte.
The isoBN electrolyte significantly reduced lithium-ion desolvation energy, maintaining 94.2% capacity retention even after 300 cycles of 15-minute fast charging without lithium plating.
Professor Nam-Soon Choi stated, “We have presented an anode interface layer technology and electrolyte system that drastically reduce the charging time of lithium-ion batteries. This marks significant progress in accelerating the widespread adoption of electric vehicles due to reduced charging times and is expected to find practical applications in future energy storage systems (ESS), drones, the aerospace industry, and other sectors.”
This research, conducted by Professor Nam-Soon Choi, researchers Chae-Eun Song, Seung-Hee Han from the Department of Life Chemistry, Professor Seung-Beom Hong, and Young-Woo Choi from the Department of Materials Science and Engineering as joint first authors, was published in ‘Advanced Materials’ on March 11.
Meanwhile, this research was supported by the High-Power Battery and Charging System Technology Development Project for Electric Vehicles by the Korea Institute of Industrial Technology Evaluation and Planning and the Nano Material Technology Development Project by the National Research Foundation of Korea.