Layered Ionogel-Polyelectrolyte Membranes for Safer and High-Performance Energy Storage Systems

A membrane composed of alternating ionogel and polymer layers features uniformly distributed charge-carrying particles within the polymer sheets. Image credit:​ ORNL, U.S. Dept. of Energy

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Researchers at the Oak Ridge National Laboratory, a facility of the US Department of Energy, have developed a novel energy storage membrane that offers a safer and more efficient pathway for electrical charge transport. The study advances fundamental understanding of how functional groups influence the mechanical robustness and electrochemical performance of highly charged polyelectrolyte membranes, which are critical components for regulating ion movement in energy storage devices. By addressing longstanding limitations such as flammability, mechanical failure, and short operational lifetimes, the work provides a promising foundation for next-generation energy storage technologies.

The newly developed system employs a layered architecture in which ionogels, hybrid materials with both liquid-like ionic conductivity and solid-like structural integrity, are sandwiched between ultrathin, flexible polymer sheets. This layer-by-layer design achieves an effective balance between high ionic conductivity and mechanical strength, enabling the membrane to function simultaneously as both electrolyte and separator. Unlike conventional liquid-electrolyte systems, the pseudosolid polyelectrolyte membranes eliminate the need for flammable liquid electrolytes while maintaining efficient ion transport at room temperature.

A key advantage of the design is its ability to suppress lithium dendrite formation, a major safety concern in lithium-metal energy storage systems. The mechanically reinforced membranes resist puncture and withstand internal stresses caused by gas evolution during overcharging, thereby reducing the risk of short circuits and thermal runaway. The laboratory testing demonstrated stable and efficient performance over hundreds of charge–discharge cycles under conditions that typically degrade conventional systems, highlighting the membrane’s durability and long-term cycling capability.

The research holds significant potential for applications ranging from consumer electronics and portable medical devices to aerospace systems, while also supporting national priorities in energy innovation and advanced manufacturing. Looking ahead, the team aims to scale up membrane production using robotic automation through ORNL’s Autonomous Chemistry Lab, enabling rapid and reproducible fabrication of multilayer membranes for commercial energy storage devices.​
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Source: Oak Ridge National Laboratory