COLLEGE PARK, Md. – Inspired by the structure of wood, engineers at the University of Maryland (UoM) have used modified wood as a unique architecture for the negative electrode of a lithium (Li) metal battery, seeking to prevent some of the key factors that lead to battery failure.

Lithium ion shuttling in rechargeable batteries provides energy to power your phone, laptop, or even just a light bulb. When the battery is charged, the lithium metal expands; and when it is discharged, the lithium metal deflates. This rapid change in size can lead to an undesirable side effect: branch-like growths of lithium on the surface of the lithium metal. The damage builds up over time and can pose safety hazards like overheating or fire.

Now, a safer battery from Ying Zhang, a UMD Ph.D. student in the Department of Materials Science and Engineering, uses wood to boost the energy density of a battery; thereby increasing the power available for portable electronics and electric vehicles, while reducing the risk of the battery overheating.

In this new type of battery, instead of storing lithium particles (ions) in a metal block, lithium is stored in the natural channels of carbonized wood – channels that were once used to carry water and nutrients.

UoM researchers say the wood acts as a “hotel” to provide lots of rooms (channels) to accommodate many guests (lithium metal). As the lithium metal “guests” enter this wood hotel, it can accommodate them all, storing them comfortably and securely in each room while maintaining the wood’s rigid exterior structure. The number of lithium particles (guests) can increase and decrease within each room, but the overall structure will not be damaged or collapse.

“This is part of our ongoing research to use natural materials to improve batteries,” said group leader Liangbing Hu, associate professor in the Department of Materials Science and Engineering and a member of the University’s Energy Research Center (UMERC). “Using nature’s bio-structure, we can find inspiration to create new ways of storing energy, and we can use renewable materials, too.”

Source: University of Maryland Energy Research Center