Thanks to new technologies like fuel cells and magnetic induction batteries, upcoming developments in portable chargers are making it easier to stay powered up on the road.

Travellers can find an app for nearly anything they want, but sadly there isn't yet an app to extend the chronically dwindling battery life of a smart phone, which always tends to die at the most inconvenient moment. But upcoming developments in portable chargers (that do not have to be plugged in) are making it easier for you to pack an emergency power supply and keep your conversation going.

The most promising breakthrough in portable chargers is the use of fuel cells, a technology that creates a current from a chemical reaction. Some fuel cells can charge a device roughly 12 times before needing a replacement cartridge of butane (which the US government permits in checked luggage on airplanes). That kind of performance is unheard of in today's plug-free chargers, which tend to be powered by conventional alkaline or lithium ion batteries and often can only last for one or two charges before needing replacement or recharging on their own.

Travellers will have to wait until this autumn to get their hands on the most anticipated fuel cell-powered charger, when US-based retailer Brookstone unveils its micro-USB power charger. The device will have enough electricity-generating oomph to fully juice up a depleted iPhone 4S or similar smart phone between 10 and 14 times. After fulfilling its duty, the shiny device will need a replacement cartridge of fuel, which will cost a few dollars. Brookstone says its adapter will work with Apple and Android smart phones as well as with any device with a micro-USB cord, such as a Kindle Fire or a tablet computer. The name of the Brookstone-branded power charger, as well as its price, won't be announced until later this year.

Meanwhile, during the past week, a handful of other companies announced developments in mobile electronic chargers that use innovative technologies to prevent devices from conking out. Here are four chargers that stand out in the crowd:

A charger that runs on easy-to-find alkaline batteries
Nothing beats the convenience of alkaline batteries, given that nearly every store in the world sells them. So this week Energizer launched a line of portable chargers that run on AA batteries. One of its products, the Instant Charger, needs only three AA batteries to revive a dead smart phone. The charger will come in two versions: one for the iPhone and one for devices that have a USB port, including most Android smart phones and all Amazon Kindles. The Instant Chargers work as fast as traditional chargers and will be available in the United States this autumn.

Harness the sun
If using alkaline batteries strikes you as wasteful, turn instead to a charger that uses solar energy. It takes about five hours for Suntactic's sCharger-5 to absorb enough rays of natural or artificial light to give a typical smart phone full power. It's one of the only solar chargers on the market efficient enough to power energy-intensive smart phones. It can soak up light while you're on the go, and it can revive a device nearly as quickly as a conventional charger. The approximately six-by-11in panel fits most any mobile phone, such as iPhone, Android and HTC.

A smart phone case with a built-in plug
The JuiceTank is a handy case that snaps onto your iPhone 4 or 4S and provides an integrated wall-charging plug, so that you can connect it to any US power socket -- no more forgetting your charger as you run out the door. The hard case is also surprisingly trim, thanks to its foldable prongs. JuiceTank’s first cases, which will go on sale this summer, will only be made for the iPhone 4 and 4S. The manufacturer, Get Detached, said cases for other smart phone models will follow. As of now, JuiceTank cases are only available to people who make donations to the start-up company via the fundraising site Kickstarter.

World's most stylish device charger
For his fall fashion collection, British designer Richard Nicoll will launch a glamorous handbag that is capable of discreetly charging a smart phone or tablet. The bag has a battery charger that runs on magnetic induction, a technology that's already behind most rechargeable toothbrushes, using unnoticeable internal magnets to generate the necessary juice. When you return to your hotel or home, you can connect the handbag to a traditional power source. An LED charm that hangs off the side of the bag lets you subtly know the remaining battery life at all times. The carryall doesn't have a name; simply visit a luxury store and ask for the latest Richard Nicoll tote.

Sean O'Neill is the tech travel columnist for BBC Travel