Wood-based materials can improve the safety and lifespan of lithium-ion batteries

For consumers worried about the risks associated with the use of lithium-ion batteries, from cell phones to laptops, laptops, electric vehicles and electric vehicles, Michigan State University has discovered that natural materials in wood can improve battery life while improving battery safety.

Chengcheng Fang, an assistant professor in the Faculty of Engineering, and Mojgan Nejad, an associate professor at the University of Agriculture and Natural Resources, can work with engineer lignin, a natural wood that provides support and rigidity, to work with thin film separators that can be used in lithium-ion batteries to cause fire.

“We wanted to build a better battery,” fans said. “But we wanted it to be safe, efficient and sustainable.”

Within a battery, positively charged cathode and negatively charged anode electrodes help with electricity flow. To maintain these electrodes, commercial separators are usually made of polyethylene and polypropylene plastic materials and can be reduced at temperatures near 100°C. Without separator protection, the cathode and anode sides of the battery can be touched, causing accidental shorts and possible fire or explosion.

In contrast, the lignin-based separator remained stable and did not reduce size to a temperature of 300°C.

Fang and her team tested lignin of various thicknesses and found that the 25 micrometer film was thinner than a quarter of human hair, stabilizing the inside of the battery and preventing the anode and cathode from connecting.

Using lignin film in the battery had another advantage. Improved in-battery stability also resulted in improved cycle life, or multiple times the battery was recharged and used.

“I was surprised that lignin film also improved the battery cycle life,” Fan said. “We’ve increased the battery cycle life by 60%.”

The third advantage of this study is that it is environmentally friendly. The team was able to manufacture the lignin separator using a low-cost drying process. This meant that the team could produce large quantities of lignin films on demand, avoiding the use of harmful solvents commonly used in environmentally harmful traditional separator manufacturing.

In this case, researchers were able to use lignin and other materials that provide 100% raw material conversion to make films without creating waste or contamination.

“Lignin, especially lignosulfonic acid, is naturally rich and does not require further treatment to function in the battery,” Fan said. “This work illustrates a new design pathway to improve both the safety and manufacturability of battery materials.”

This study is published in Advanced Materials, and the technology is suspended patents through the MSU Innovation Center.