Lithium-ion batteries power everything from smartphones to electric vehicles, but safety remains a major concern. While they are efficient and long-lasting, battery failures can lead to dangerous consequences. In fact, the rise of electric vehicles (EVs) has made this issue even more pressing, with over 20 EV fires or explosions in recent years linked to lithium-ion battery failures.

A groundbreaking study published in ACS Applied Materials & Interfaces introduces a new sensor that could help mitigate these risks and prevent catastrophic battery failures. As lithium-ion batteries become more widespread in smartphones, laptops, electric vehicles, and military applications, the need for safety innovation has never been more urgent. Though these batteries are known for their high energy density and long lifespan, they also pose serious hazards. Overheating or damage to battery cells can release volatile gases, which may ignite, leading to fires or explosions. As a result, developing gas sensors that are sensitive, selective, cost-effective, easy to integrate, and energy-efficient is crucial for improving lithium-ion battery safety.

Researchers have developed a sensor that can detect trace amounts of ethylene carbonate (EC) vapor—one of the key components of a battery’s electrolyte. EC vapor is released when the battery is stressed or damaged, and it can be an early warning sign of potential failure. By detecting these vapors early, the sensor could significantly improve battery management systems, preventing dangerous malfunctions and enhancing the overall reliability of lithium-ion technology.

Zhao, one of the lead researchers on the project, explained that their work is driven by the urgent need for safer batteries. “Our goal is to provide an early detection mechanism for electrolyte leaks, which can help prevent failures before they escalate into major safety issues.”

The new gas sensor, developed using covalent organic frameworks (COFs), is the first of its kind to be designed computationally for EC detection. COFs are molecular structures engineered to selectively detect specific gases, and the researchers used advanced computational methods to screen hundreds of potential materials before settling on COF-QA-4 as the best candidate for the job.

COF-QA-4 is highly sensitive to EC vapor while ignoring other gases, making it an ideal solution for detecting leaks long before they become hazardous. In laboratory tests, the sensor demonstrated outstanding performance, able to detect EC vapor at concentrations as low as 1.15 parts per million (ppm). This high level of sensitivity is critical for identifying early warning signs and preventing dangerous battery failures.

“We screened hundreds of materials before identifying COF-QA-4 as the optimal candidate. It’s not only sensitive but also highly selective, targeting EC gas while ignoring other vapors,” Zhao said. “This allows the sensor to detect leaks well before they become a threat.”

While the immediate application of the sensor is in electric vehicles, its potential extends far beyond that. The sensor could be integrated into battery management systems for smart home devices, industrial safety systems, and other applications that rely on lithium-ion technology. By providing real-time alerts for hazardous gas leaks, the sensor could serve as an early warning system to prevent catastrophic accidents, saving lives and protecting property.

According to Zhao, integrating this sensor into existing battery management systems would allow manufacturers to take proactive steps to mitigate potential risks, preventing dangerous situations before they escalate. “By detecting potential issues at an early stage, this sensor could help avoid fires, explosions, and other battery-related hazards,” he said.

As the demand for lithium-ion batteries continues to grow, ensuring their safety will be critical in avoiding dangerous failures. This new sensor represents a significant step forward in making batteries safer, providing a proactive solution to one of the most pressing challenges facing battery-powered technology today.

By Impact Lab