Batteries usually contain harsh chemicals that make them less than environmentally friendly. But lately, researchers from the University of Maryland have created a long-lasting rechargeable battery from wood!
The most common rechargeable batteries today are based on lithium-ion technology. In these cells, lithium ions carry the current by moving from the negative to positive electrode. That discharges the stored power and the cell phone gets the necessary juice. Based on this same concept, professor Hongli Zhu along with his team has succeeded in creating a nanoscale rechargeable battery from the most environmentally friendly material — wood.
As batteries charge and discharge, they swell slightly. This will slowly break down the stiff materials. The cellulose fibers, gathered from yellow pine trees, are naturally flexible and can withstand this strain. These properties make wood an excellent material to hold liquid electrolytes and be an active part of the battery.
After being coated with a thin layer of tin, the fibers can maintain the battery’s integrity for over 400 charging cycles. After being run through charge-discharge cycles, the fibers were wrinkled, but intact enough to still act as an efficient ion transport medium, which is why the cell still works. The long-lasting battery from wood relies on sodium instead of lithium.
The lower energy density of sodium-ion means this technology won’t change your smartphone’s battery into a block of wood any time soon. Instead, these wood-based batteries could be used on a larger scale to store huge amounts of energy at solar power plants and industrial facilities. Here’s a video for you.
At present, the researchers at the University of Maryland are working with sodium-ion cells that are 1000-times thinner than a sheet of printer paper. The team believes this same technology could serve as a template for a new generation of low-cost sodium-ion batteries.
Source: Extreme Tech