The electric vehicle market is experiencing explosive growth, with global sales exceeding $1 trillion (approximately 1,283 trillion won) in 2022, and domestic sales exceeding 108,000 units. Inevitably, the demand for high-capacity batteries that can extend the cruising range of EVs is increasing. Recently, a joint team of researchers from POSTECH and Sogang University developed functional polymer binders for stable high-capacity anode materials that can extend the current EV range by at least 10 times.
A research team led by Professors Soojin Park (Department of Chemistry) and Youn Soo Kim (Department of Materials Science and Engineering) of POSTECH and Professor Jaegeon Ryu (Department of Chemistry, Biomolecular Engineering) of Sogang University, has developed a high-capacity charged polymer binder. A negative electrode material that combines stability and reliability, achieving a capacity that is more than 10 times that of conventional graphite negative electrodes. This breakthrough was achieved by replacing graphite with a Si anode combined with a layered charged polymer while maintaining stability and reliability. The research results were published as a cover article of Advanced Functional Materials.
High-capacity anode materials such as silicon are essential to create high-energy-density lithium-ion batteries. It can provide at least ten times the capacity of graphite or other anode materials currently available. The challenge here is that the volume expansion of high-capacity anode materials during reaction with lithium threatens battery performance and stability. To alleviate this problem, researchers have investigated polymer binders that can effectively control volumetric expansion.
However, previous studies have focused only on chemical cross-linking and hydrogen bonding. Chemical crosslinks involve covalent bonds between binder molecules, making them solid, but with a fatal flaw: once broken, the bonds are irreversible. It is a reversible secondary bond between molecules caused by , but its strength (10-65 kJ/mol) is relatively weak.
The new polymer developed by the research team not only makes use of hydrogen bonding, but also Coulomb force (the attraction between positive and negative charges). These forces have strengths of 250 kJ/mol, much higher than hydrogen bonds, but are reversible, making volume expansion easier to control. The surface of the high-capacity anode material is mostly negatively charged, and the layered charged polymer has an array of alternating positive and negative charges that bind effectively to the anode. Additionally, the team introduced polyethylene glycol to adjust the physical properties and facilitate the diffusion of lithium ions. The result is a thick, high-capacity electrode and maximum energy density found in lithium-ion batteries.
Professor Soojin Park explains: Silicon-based anode materials have the potential to increase mileage by at least a factor of ten. ”
Original: Innovative battery technology that extends EV cruising range by more than 10 times
Than: Pohang University of Science and Technology | Sogang University
