Leaves become batteries! University of Maryland recently invented a new environmental friendly battery with oak leaves and some sodium.

Researchers first bake the oak leaves under 1,000 degrees Celsius till they carbonize, then put them in sodium. The back of oak leaves are covered with pores which were used to suck up water now are absorbing electrolyte of sodium. While the front of the leaves has turned into carbon in nanostructure which can take in sodium carries electric charge. Hence the whole process forms the positive and negative sides of the sodium battery.

The interesting thing is that sodium-sulfur battery and lithium battery came out to the market almost the same time. Even though sodium-sulfur battery has a higher efficiency, its battery cycle life is much shorter than lithium battery due to its undesirable electrode materials. Many scientists have been working on this issue for a very long time.

Leaves are very common in daily life. According to the researchers at University of Maryland, they also tried with wood fiber as a material for sodium battery. It turned out leaves work for the best based on its shape and structure. Researchers now are planning to use different types of leaves for battery-making, hoping to find the best in thickness, structure and elasticity as electrical energy storage.

Researchers of the University do plan to commercialize battery made of leaves just yet. Their research result will be published on the next issue of ACS Applied Materials & Interfaces.