The future of the battery: Coke, metal or leaves?

The future of mobile phone and laptop battery technology will not be based on sugary soft drinks, despite widespread media coverage of a Nokia mobile phone that apparently runs on Coca Cola.

Details of a Coca Cola-powered mobile phone were recently published by Chinese designer Daizi Zheng. On her site, Zheng claimed "all that is required is a small supply of a sugary drink... Bio-batteries are fully biodegradable and have, on a single charge, a potential life-span three to four times longer than conventional lithium batteries."

But some reports quote Zheng admitting that the Coke battery "would struggle to generate enough power needed to make a call" and a production model is many years away.

According to Adam Best, an energy research scientist at the Commonwealth Scientific and Industrial Research Organisation (CSIRO), the Coke-powered phone battery might seem like a good idea but in reality it is unlikely to be very efficient and could turn out to be relatively expensive.

Dr Best said Zheng's battery most likely makes use of the phosphoric acid in Coke, which also makes the soft drink an excellent industrial cleaner - it is used by hospitals to keep catheters clean and US police reportedly use it to wash blood off the road.

"You are not going to make large-scale batteries out of that, that is for certain. However, in terms of maintaining your battery, all you have to do is go buy a can of Coke and chuck it in, so you know it is going to cost you about $1.25 to refuel," Dr Best told iTnews.

he said that cutting-edge battery technology is based around  making electrodes that can store more energy; these tend to be metal phosphates - lithium ion being one of the most common - and oxides. Secondly, storing that energy safely.

Electricity is created when ions in the electrolyte move between the electrodes. The problem is, according to Dr Best, that most electrolytes will only work safely at a certain voltage.

"If you try and use some of these new electrodes that have a higher open circuit voltage, which means you can store more energy, then you need safer electrolytes. These have not yet been discovered or invented.

"Also, working those electrolytes at such high voltages leads to decomposition that can lead to reactivity issues, instability, which can lead to fires and explosions," he said.

A simple Google search reveals the extent of this problem. Most major hardware vendors, including Apple, Dell and Nokia, have had to replace or recall batteries in recent years after complaints about explosions and fires.

Dr Best said he is working on making high-power batteries safer by using chemicals that stop reacting when they heat up.

"What we are doing is engineering ions so that when you put them together you get a liquid at room temperature ... one of the positives with this system is that when you heat them up they have no volatility - not to say that all ionic liquids have no volatility because you can engineer them to have specific properties.

"The lightest and most energy dense electrode of all is lithium metal and we are looking at ionic liquids which are highly stable to lithium metal. We have been able to demonstrate recently that we can cycle lithium metal for hundreds of cycles at very high current densities and without any issues of dendritic growth, which is a very big safety problem," he said.

Dr Best hopes that the battery technology he is working on will provide up to 30 percent more battery life, without the risk of an explosion.

Bio Fuels

Alternatives to crude oil are evolving rapidly, which is no surprise considering the volatile price of black gold.

Victoria Haritos, who heads up the CSIRO Entomology Division's Biological Chemistry Team, said Australia could become a serious producer of bio fuels using common materials such as leaves and twigs.

In a podcast interview published on the CSIRO website, Dr Haritos explains that we use foodstuffs such as cane sugar, wheat starch and canola seeds, to create bio fuel. She says these could easily be converted to use lignose cellulose, which is a raw material for creating bio fuels made from plant leaves and twigs.

"We can see a great potential for this in Australia. We have the potential to grow a lot of lignose cellulose and we have a lot of land suitable for growing this fuel.

"We are also making fuels out of oils from oil seeds - like canola seeds  - to make bio diesel but we also see great potential in the use of lignose cellulose, plant leaves, plant wood to convert that into bio fuels because there is just so much more of it and it grows so much faster with so much more bio mass in a shorter time. It has the potential to expand the industry while not at all competing with food," said Dr Haritos.

She says creating the equivalent of a barrel of crude oil using lignose cellulose will cost $40 to $60. The price of crude oil is about US$78 ($A84).