Capitol News

For consumers concerned about the risks associated with lithium-ion batteries, Michigan State University researchers have found a natural material from wood that can enhance battery safety and longevity.

Chengcheng Fang, an assistant professor in the College of Engineering, and Mojgan Nejad, an associate professor in the College of Agriculture and Natural Resources, collaborated to engineer lignin—a natural component of wood—into a thin film separator for use inside lithium-ion batteries. This innovation aims to prevent short circuits that can lead to fires.

"We wanted to build a better battery," said Fang. "But we also wanted it to be safe, efficient and sustainable."

Inside a battery, positively charged cathode and negatively charged anode electrodes facilitate electricity flow. A commercial separator typically made from polyethylene and polypropylene plastics keeps these electrodes apart but can shrink at temperatures near 100 degrees Celsius. Without this protection, the cathode and anode could touch, causing short circuits or potential fires.

In contrast, lignin-based separators remained stable up to 300 degrees Celsius without shrinking.

Fang's team tested different thicknesses of lignin films and found that those measuring 25 micrometers were most effective in maintaining battery stability and preventing electrode contact.

Using lignin films also improved the battery’s cycle life by 60%. "We were surprised to see that the lignin film also improved the battery’s cycle life," said Fang.

Another advantage is environmental sustainability. The team manufactured lignin separators using a low-cost dry processing method without harmful solvents, allowing for large-scale production without waste or pollution.

"Lignin, particularly lignosulfonate, is naturally abundant and it doesn’t need any further treatment to function in batteries," said Fang. "This work demonstrates a new design pathway to improve both the safety and manufacturability of battery materials."

The research was published in Advanced Materials, with technology patent pending through the MSU Innovation Center.