Revolutionizing EV Battery Technology: A Gel-Like Solution for Extended Lifespan and Enhanced Safety
The quest for longer-lasting and safer electric vehicle (EV) batteries has led researchers at UNIST to develop a groundbreaking gel-like material that could revolutionize high-voltage EV battery technology. This innovative electrolyte, known as An-PVA-CN, actively prevents the formation of reactive oxygen species (ROS), which are the primary culprits behind battery aging and swelling. By extending battery lifespan by 2.8 times and reducing swelling by one-sixth, this electrolyte offers a promising solution for long-distance EV driving.
Led by Professor Hyun-Kon Song and his team, the research focused on high-voltage lithium-ion batteries (LIBs) that operate above 4.4V. While these batteries offer increased energy storage, they also pose risks. The higher voltage can destabilize oxygen in the nickel-rich cathode, leading to the formation of ROS, which produce gases and heighten the risk of explosions while shortening battery life.
The An-PVA-CN gel polymer electrolyte (GPE) developed by the team introduces an anthracene-based semi-solid gel electrolyte that actively prevents the release of ROS from the electrodes during high-voltage charging. The anthracene component binds with unstable surface oxygen, preventing it from forming ROS, known as singlet oxygen (1O2), which act as seeds for further degradation. This dual-layer protection ensures that existing reactive oxygen is captured and removed.
Additionally, the nitrile (-CN) group in the electrolyte stabilizes nickel metal in the cathode, preventing dissolution and structural deformation during charging. This comprehensive approach to oxygen redox regulation and transition metal redox control effectively mitigates oxygen gas evolution and transition metal dissolution.
The results are impressive. Batteries equipped with this electrolyte maintained 81% of their initial capacity after 500 charge-discharge cycles at a high voltage of 4.55V, whereas conventional batteries dropped below 80% capacity after only 180 cycles. This indicates a nearly threefold increase in lifespan. Furthermore, gas evolution and swelling were significantly reduced; the gel electrolyte limited expansion to approximately 13 micrometers, compared to 85 micrometers in conventional batteries, achieving about a sixfold reduction.
Professor Song highlights the significance of this research, stating, "This study demonstrates that oxygen reactions in high-voltage batteries can be controlled at the electrolyte design stage. This principle could be applied to develop lightweight LIBs for aerospace applications and large-scale energy storage systems."
The findings of this research have been published in the online version of Advanced Energy Materials on October 5, 2025. The study was supported by the InnoCore program of Hydro*Studio at UNIST, the KEIT, and the KRICT.
This breakthrough in electrolyte technology not only extends the lifespan of EV batteries but also enhances their safety, making it a significant step towards a greener and more sustainable future for transportation.
