The electric vehicle market has experienced rapid growth, with global sales exceeding $1 trillion and domestic sales exceeding 108,000 units. However, the increasing demand for high-capacity batteries to extend the EV driving range remains challenging. Researchers from POSTECH and Sogang University have developed a polymeric binder for a high-capacity anode material that could increase the current EV range by at least 10-fold.
The research team replaced graphite with Si anode combined with layering-charged polymers to develop a functional polymeric binder that is stable and reliable, offering a capacity that is ten times or higher than conventional graphite anodes. This breakthrough was published in Advanced Functional Materials as the Front Cover Article.
POSTECH
High-capacity anode materials like silicon are crucial for creating high-energy density lithium-ion batteries. However, the volume expansion of high-capacity anode materials during the reaction with lithium poses a threat to battery performance and stability. Polymer binders have been investigated to control volumetric expansion. Still, previous research has focused only on chemical crosslinking and hydrogen bonding, which have some limitations.
The new polymer the research team developed uses hydrogen bonding and Coulombic forces, which have a strength of 250 kJ/mol, making it easy to control volumetric expansion. The surface of high-capacity anode materials is mostly negatively charged, and the layering-charged polymers are arrayed alternately with positive and negative charges to bind with the anode effectively. The team also introduced polyethylene glycol to regulate the physical properties and facilitate Li-ion diffusion, resulting in the thick high-capacity electrode and maximum energy density found in Li-ion batteries.
The research holds the potential to significantly increase the energy density of lithium-ion batteries through the incorporation of high-capacity anode materials, thereby extending the driving range of electric vehicles. The study was conducted with the support of the Ministry of Science and ICT, the Nano-Material Technology Development Program, and the National Research Laboratory for Future Technology of Korea.