Quest to extend smartphones' stamina

While sharp screens, faster processors and millions of apps are some of the selling points of mobile technology, the battery keeping your gadget alive doesn't get as much attention.

This is because the essential electrochemical process inside a battery hasn't changed much in more than a century. Until now.

Pressure from smartphone users wanting their devices to last longer between charges is helping generate a lot of battery research in labs around the world.

Transferring a current repeatedly through electrodes as a battery charges and discharges degrades the electrodes and shortens the battery's life.

Now a University of Southern California team is looking for better electrodes. It is experimenting with silicon nanoparticles to help the current move more smoothly. Nanoscale "wires" transfer current faster, promising a full charge in 10 minutes and up to three times as much energy.

"It opens the door for the design of the next generation lithium-ion batteries," USC professor Chongwu Zhou said.

While the lithium that makes up the standard of current battery technology is expensive and heavy, sodium - a related element - is found everywhere from table salt to sea water. So Michigan Technological University associate professor Reza Shahbazian-Yassar is using an electron telescope to better work out the chemistry of a flat battery and build a better model using the much more plentiful material.

"With better understanding on why batteries become dead, we hope to help battery developers," Professor Shahbazian-Yassar said. "We're studying fundamental reactions to find out what materials and electrodes will do a better job hosting the sodium."

Silicon and sodium aren't the only materials being investigated. Zinc-air batteries were theorised in the 1930s and used by the US military in the 1960s. But research into lithium-air might mean that, instead of an enclosed battery, there could be one in which electrodes gather electrons from oxygen outside to produce a current. Early tests from engineering and chemistry departments in Seoul and Rome have been encouraging, with no real difference in performance between the 20th and 100th charge cycle.

The study's authors are particularly interested in the electric car market, saying "owing to its exceptionally high energy potentiality, the lithium-air battery is a very appealing candidate for fulfilling this role".

But with a whopping 13,500Wh/kg - up to 10 times the capacity of today's lithium batteries - imagine what it could do for your handset.

Another possible solution is simply cramming more lithium ions into the battery cell and moving them around faster to generate electricity for a longer charge and faster recharge.

Northwestern University electrochemistry professor Dr Harold Kung is working on nano-scale holes through the battery that could let the electrochemical molecules move more freely.

But, he said, most researchers were working with a single element of a part that had to work in a much bigger system. "Our long-term tests were conducted for the individual component only. We need to get reliable test results in full battery configuration and usage conditions, which takes time," Professor Kung said.