When will your phone battery last as long as your Kindle?

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In the last decade, we’ve seen laptops shrink to cardboard thickness, ubiquitous Internet connectivity allow us to carry all the world’s knowledge in a pocket, and touch-based tablets make computing intuitive enough for two-year-olds. Everything seems to be improving. Well, everything with one big exception: batteries. As the rest of the tech world rips forward, battery technology remains stagnant. Smartphone clock speeds are measured in GHz and screens are so dense we can’t even see pixels anymore, yet battery life is still measured in hours, not days.

We’ve been putting up with crappy battery life for our entire lives, but our dependence on batteries is growing. More and more of us look at the battery specs of new devices to judge their overall competence, even before they’ve gone on sale, in the same way we check the screen resolution and the clock speed of the chip. The new Verizon Droid DNA is an excellent example. The 1080p, 5-inch screen may have grabbed the headlines, but the seemingly weedy 2020mAh battery had many complaining that it wouldn’t be up to the job of powering such a pixel-dense screen.

A recent J.D. Power survey found battery performance was the least satisfying aspect of smartphone ownership, and it was one of just two areas that showed a significant decline between 2011 and 2012. Owners of 4G devices are particularly frustrated by poor performance. Bottom line: Batteries need to get better, but will they? Is a single day of battery life really the best we can hope for? Fortunately, no. A number of promising developments on the horizon promise to bring batteries out of the dark ages and potentially last for weeks.

Sprucing up the lithium-ion battery

Lithium-ion batteries were developed in the 1970s and reached the market in the early 1990s. Since then, they’ve made their way into almost every battery-powered gadget. But they’re ready for retirement, right? Not according to Professor Harold Kung of Northwestern University. He led a project which redesigned standard li-ion batteries using a graphene-silicon anode so they could hold up to 10 times as great a charge as before, while decreasing the time it takes to charge them by the same amount.

Researchers at Rice University have used a similar-sounding technique to make another type of cell, this time with a porous silicon-powder anode, which again boosted performance 10 times over. While a standard graphite anode li-ion battery has a capacity of 350 to 400mAh per gram, Rice’s battery hits 1,000mAh per gram, so it can store more charge without adding bulk.

Silicon has proven popular in next-gen batteries because it’s cheap, plentiful, and can hold more power than carbon; but it has proven difficult to master the longevity of cells built using it. Battery expert Yi Cui, working at Stanford University, has developed a “double-walled silicon nanotube anode” which can provide a capacity of 4,000mAh per gram and more importantly, achieve the long-term goals always thought possible using silicon. His research states the battery will still operate at 85-percent capacity even after 6,000 cycles.

While all these new technologies can theoretically be used in small batteries powering our gadgets, much of the research is currently aimed at electric vehicles.

New types of batteries

Though there are some promising new techniques that may squeeze more juice out of them, improved li-ion batteries only represent one avenue of innovation. So what else is out there?

Li imide batteryLi-imide technology, developed by Leyden Energy, is also vying for a shot at powering your gadgets. Although the batteries are based on a different chemistry, they cost the same to produce as li-ion, and return as much as 25 percent more energy. They’re also more resistant to varying heat levels (li-ion cells don’t react well to hot and cold) and will last three times as long as existing cells too, even with a daily charging cycle.

Lithium-air, or li-air, batteries are another contender, but they’re still in development. Like much of the research into new battery tech, li-air cells will most likely find their way into cars, but could be adapted for use in consumer electronics, too. According to Professor Peter Bruce from the University of St. Andrews in Scotland, it’s currently a challenge to make li-air batteries that are stable enough to only create reactions that supply power. “The science is promising but we can’t yet guarantee it will end in a workable technology,” he told the BBC earlier this year.

One challenge of developing a new battery is the sheer variety of  potential chemical cocktails to examine. To speed up the process of deciding which could offer the best results, a computer algorithm developed by the Materials Genome Project at MIT simulates possible reactions so scientists can focus on the best candidates. A startup named Pellion Technologies is a spin-off of the project, and is currently developing a magnesium battery which could power cars, consumer electronics, and handheld devices in the future.

There have been advances in bio batteries too. Wile the idea of a Coca-Cola powered phone is good for a laugh, Toshiba and Sony have experimented with enzyme-powered fuel cells using everything from waste paper to vodka in the quest for an environmentally friendly source of power.

New ways to conserve energy

New batteries present one obvious way to improve how long a gadget can run without a recharge, but conserving the charge of an existing battery can accomplish the same feat. A team at the University of Michigan examined how phones use the most power, and found them to be particularly wasteful at idle. Constantly monitoring wireless networks for signal and incoming data uses as much energy as sending out messages. To fix this, the researchers came up with E-MiLi, which is short for Energy Minimizing Idle Listening. It’s like an ultra-power-saving mode, slowing down the connectivity processes, then giving them a kickstart when the phone detects an incoming signal. The result is a smartphone that’s 44 percent more efficient.

The downside of E-MiLi is that for it to work, the tech not only has to be built into every gadget, but all Wi-Fi and cellular hardware, as well. Kang Shin is a professor of Computing Science at U of M who works on the E-MiLi team. He revealed that the team is about to “sign a licensing agreement with a major cellphone manufacturer,” but won’t be able to provide any solid details for a couple of weeks. This could be one of the few emerging power technologies that we’ll get to see in use quite soon.

Companies are also exploring totally different ways of charging batteries, which can help negate the pain of it running out of power at an inopportune moment. Piezoelectric films can now be built into clothing, where vibration from ambient sound can supply power to a phone. Personal solar panels can store energy during the day to power hardware in an emergency as well. The U.S. military has even demonstrated clothing that stores kinetic energy and can power devices.

The future

These next-gen batteries could provide more energy, last longer, and in some cases even cost less than current batteries. It all sounds wonderful, so why aren’t any of them in our phones and laptops?

Sadly, none of them are ready for prime time yet. While Leyden has licensed its li-imide batteries to Nvidia, it will only be used in development platforms. Meanwhile, Professor Bruce from the University of St Andrews says he believes lithium-ion batteries are “here to stay” for at least another few years.

Here’s hoping those alternatives can offer us a power boost in the meantime. It’s going to be a while before any phone battery lasts as long as a Kindle.

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