US-Made Superionic Polymer Unlocks Faster, Safer Solid-State EV Batteries

US scientists at Oak Ridge National Laboratory have developed a novel superionic polymer addressing key challenges in solid-state batteries. This innovative material enables ions to move up to 10 billion times faster, creating a superionic state crucial for safer, more efficient, and practical electric vehicle batteries. By tuning the polymer's structure with zwitterions, researchers created optimal ion-conducting channels. This breakthrough could also benefit fuel cells and grid storage, significantly advancing energy technology.

Researchers at the Department of Energy’s Oak Ridge National Laboratory (ORNL) have engineered a groundbreaking superionic polymer, poised to revolutionize solid-state battery technology. This discovery tackles a major hurdle: the sluggish movement of ions within electrolytes, which has limited the efficiency and practicality of solid-state solutions. While traditional batteries rely on liquid electrolytes, the shift towards solid-state designs offers enhanced safety and performance. However, existing solid electrolytes like ceramics are brittle, and conventional polymers suffer from poor ion transport. The ORNL team's innovative solution involved carefully controlling the chemical composition of a lithium salt-based polymer. By precisely adding molecular groups called zwitterions, which carry both positive and negative charges, they successfully tuned the polymer's structure. This created small pockets where ions could cluster, eventually connecting into continuous, channel-like pathways. This network allows ions to hop efficiently through the material with minimal resistance, achieving a superionic state where ions move orders of magnitude faster—up to 10 billion times quicker than their surroundings. An optimal configuration was identified when approximately 80 percent of the polymer units were functionalized, enabling the formation of stable, ion-conducting channels. This significantly improves the material’s conductivity, making solid-state batteries safer, more efficient, and practical for electric vehicles, fuel cells, and grid storage applications. Future work will investigate the polymer's superionic behavior at a molecular level using advanced computational techniques.