New York, Oct 24 (IANS): Researchers have developed a new method to increase the energy density of lithium (Li-ion) batteries used in smartphones, tablets and other portable electronics -- a discovery that can improve their performance by 10-30 per cent.

Yuan Yang, assistant professor of materials science and engineering at Columbia Engineering, built a tri-layer structure that is stable even in ambient air, which makes the battery both long lasting and cheaper to manufacture.

When lithium batteries are charged for the first time, they lose anywhere from 5-20 per cent energy in that first cycle.

"Through our design, we've been able to gain back this loss, and we think our method has great potential to increase the operation time of batteries for portable electronics and electrical vehicles," said Yuan.

His method lowered the loss capacity in state-of-the-art graphite electrodes from 8 per cent to 0.3 per cent and in silicon electrodes, from 13 per cent to -15 per cent.

Yang's group is now trying to reduce the thickness of the polymer coating so that it will occupy a smaller volume in the lithium battery, and to scale up his technique.

"This three-layer electrode structure is indeed a smart design that enables processing of lithium-metal-containing electrodes under ambient conditions," notes Hailiang Wang, assistant professor of chemistry at Yale University, who was not involved with the study.

The work was published in the journal Nano Letters.