Tech firms lead the assault on batteries

How many of us get more than 24 hours from our smartphone before it runs out of juice? The biggest barrier to mobile computing has been short battery life. The problem with power is portability. So if we're to use ever more mobile computing devices - such as smartphones, tablets, laptops, smart watches and eventually wearable heads-up displays and powered clothing - some innovation is required.

We have a plethora of add-on accessories to help us eke a little more from our mobile devices, such as the Mophie Juice Pack Powerstation, an external battery costing HK$648 that can refill an iPhone5 a few times over before it needs its own recharge. It claims to recharge up to four times faster than using traditional USB batteries. There is also the Eton BoostBloc 6600, a HK$788 device that will charge a tablet or smartphone three times, while those on an outdoor trip could find room for Goal Zero Yeti 1250, a suitcase-sized battery with an optional solar panel that can charge a laptop for well over a week. However, it costs HK$14,000 and weighs 47kg.

But these solutions are only temporary. Ubiquitous Energy uses a molecular pow er film to charge a device as it's being used. "The film is transparent in the visible part of the light spectrum, and absorbs in the near infra-red to generate energy," says Dr Kevin Curran, senior member at the Institute of Electrical and Electronics Engineers, who reckons that the technology will first be used to power E Ink displays of devices such as Amazon's Kindle.

New ultra-thin plastic-based E Ink displays that use very little power will be used later this year on the YotaPhone, a two-screen smartphone whose regular power-hungry LCD screen will be used only for watching video. The reason for the "comeback" of E Ink - a display technology thought to be on its way out with the birth of tablets such as the iPad and Kindle Fire - is the increasing size of screens.

As six-inch displays become common, there's a move to create more power-efficient devices and re-introduce electronic paper. Firms are also working on wireless charging. That's achieved by a process of electromagnetic induction in which a current is sent from a coil in a charging pad to a coil in a gadget, but it works across only a few centimetres.