Wood power


Wood is a bad conductor of electricity but can do wonders when used inside a battery. Extremely small tin-coated wood scraps have been used to make an environment-friendly, thinner-than-paper, long-lasting, sodium-ion battery that can withstand hundreds of charge-discharge cycles. During charging and discharging, regular batteries swell slightly.

This, over time, breaks down the stiff material used to store electrolytes in most batteries. But cellulose fibers in the wood are naturally flexible and assist in the flow of mineral-rich water across the length of tree. They can thus withstand the strain associated with electron flow in batteries. The technology could serve as a template for a new generation of low-cost sodium-ion batteries. 


Down to Earth, July 2013