The battery produces electricity from the air

Lithium ion batteries used by laptops and mobile phones are approaching technical limits. But British chemists claim they have found a way to increase the battery's power by tens of times.

Battery samples using oxygen from British chemists.Photo: Newscientist.

The standard Lithium ion (Li-Ion) battery has a graphite electrode, graphite electrode, lithium cobalt oxide (LiCoO ₂ ) and lithium salt electrolyte. Lithium ions move back and forth between the two electrodes during the process of charging and discharging electricity, electrons to the external circuit to serve the device.

According to Peter Bruce, a lecturer at the University of St Andrews (UK), the disadvantage of Li-Ion batteries is that LiCoO ₂ takes up a lot of space and is quite heavy. He said that he could borrow ideas from zinc batteries for hearing aids. These batteries generate electricity through the reaction of zinc molecules and oxygen in the air. So Bruce teamed up with colleagues at Strathclyde University to build a Li-Ion battery using oxygen.

New batteries have a higher energy density than Li-Ion batteries because they do not contain LiCoO ₂ anodes. Instead, the positive electrode is made of porous carbon, while lithium ions are 'compressed' into the electrolyte that flows through the carbon sheet.

When the battery discharges electricity, oxygen from the air will overflow through a membrane to penetrate the porous carbon - where it reacts with Lithium ions in the electrolyte and electrons from the external circuit to form Lithium oxide (Li ₂ O ) in solid form.

Li ₂ O gradually occupies the gap in the positive electrode during battery discharge process. But when the rechargeable battery Li ₂ O will separate, release Lithium ion again and get rid of the holes inside the carbon electrode. Oxygen escaping will return to the air.

'By using oxygen in the air, we will reduce the volume and volume of Li-Ion batteries. The battery uses oxygen like a fuel cell in that it takes reactants from outside the system , 'Bruce said.

The battery tested by Bruce Group has an energy ratio of 4 Ampere / g, 8 times higher than the Li-Ion battery for mobile phones. The design team confirmed that it is feasible to raise this ratio to 10. Meanwhile, if you improve the standard Li-Ion battery, you can only double the power output.

Saiful Islam chemist, a battery expert at Bath University (UK) but did not participate in the study, said: 'To my knowledge, Lithium batteries use air to increase the density of charge. 8-10 times. However, we still need to research to understand the processes that take place inside new batteries. It will help optimize the technology so that batteries that use oxygen can become a commercial product . '

Bruce and colleagues are looking to reduce the size of new batteries so they can fit in mobile electronics.