Scientists have taken a leaf from the book of nature and developed a thin, long-lasting, efficient and environmentally friendly battery that uses wood.
According to Design and Trend, the components in the battery, tested by scientists at the University of Maryland, are a thousand times thinner than paper.
Researchers Liangbing Hu, Teng Li and others emerged from their smoke filled labs having made a battery built around a sliver of wood coated with tin.
They think it is much better than batteries that use stiff, non-flexible substrates. Current batteries are too brittle to withstand the swelling and shrinking that happens as electrons are stored in and used up from the battery.
Hu said that idea came from looking at trees. Wood fibers that make up a tree once held mineral-rich water, and so are ideal for storing liquid electrolytes, making them not only the base but an active part of the battery.
They used wood as the base of an experimental sodium-ion battery, choosing sodium over lithium.
Sodium does not store energy as efficiently as lithium, so would not be as much use in mobile phones – instead, its low cost and common materials would make it ideal to store huge amounts of energy at once such as solar energy at a power plant.
The team noticed that after charging and discharging the battery hundreds of times, the wood ended up wrinkled but intact. Computer models showed that that the wrinkles effectively relax the stress in the battery during charging and recharging, so that the battery can survive many cycles, putting it among the longest lasting of all sodium-ion nanobatteries.
Wood fibers are soft enough to serve as a mechanical buffer, and so can accommodate changes in tin, which the researchers say is key to their long-lasting sodium-ion batteries.