The search for a better battery

The vast technological progress that has been made since the invention of the computer chip in the mid-20th century can be simply told in one story:Moore’s Law. Every couple of years, the number of transistors – the switches whose “on” or “off” functions are the building blocks of computing – that can fit on a chip doubles. Paired with other technology improvements, this has meant processors doubling in power every 18 months.

Moore’s Law has held remarkably steady for more than 40 years since it was first coined. It explains the amazing advances in electronics in just a generation; it’s the reason the smartphones in billions of pockets are thousands of times more powerful than the best computers of a few decades ago.

But when it comes to the batteries that power these devices, there is no equivalent to Moore’s Law. The lithium-ion technology present in a smartphone or laptop hasn’t changed significantly since it was first commercialised by Sony in 1991. What powers our cars is even more ancient: the fundamental designs of the internal combustion engine and lead-acid batteries in every popular vehicle have barely changed in decades.

For much of the history of these designs, there has been little incentive to change them – they have worked perfectly well for a long time, and batteries were rarely front of mind. Mobile phones in the early 2000s would last days on end without being charged.

Upon prising off the screen, the team noticed the battery is slightly smaller than in its iPhone 6 predecessor, partly due to the new taptic engine underneath it.The lithium-ion battery inside the latest iPhone  Photo: iFixit

In the last decade though, the smartphone era has rendered current battery technology woefully inadequate. The latest iPhone is 16 times more powerful than the one Steve Jobs unveiled nine years ago, but the battery still lasts just a day.

Given the chasm in power between the two, this is a feat of engineering, but it is one that has been achieved through more efficient processors, not better batteries. In terms of milli-Ampere hours – a measure of battery capacity – there has been just a 22 per cent improvement between the original iPhone in 2007 and last year’s 6s model.

The challenges of lithium-ion

The design of a lithium-ion battery is relatively simple. When a battery is being charged, electrons flow through a circuit to a negative electrode, attracting lithium ions – electrically-charged particles – that are contained in a solution known as an electrolyte. When the battery is being used, those ions transfer to a negative electrode through the solution, in the process releasing electrons that then power the device.

It is fairly-basic chemistry, and as a result, is difficult to tinker with. There are only so many elements, and lithium has been shown to be the best of these for the task at hand. Improvements tend to come from tweaking the chemical makeup of the electrodes or electrolyte, but are gradual and become more difficult over time. Despite the huge focus on batteries from technology’s richest companies, capacities tend to improve at around 5pc a year. In fact, many manufacturers have found the best way to improve batteries has simply been to make them bigger, thus allowing room for more ions.

For most people, this is simply not good enough. Our smartphones are moving from an important to a fundamentally necessary part of our lives. We pay for things with them, used them to communicate, and rely on them for navigation. If they fail, it’s distressing. But this is nothing compared to anelectric car, or a lifesaving health device, running out of power. And solar power, expected to account for a major part of our energy consumption in the future, will require high-capacity storage for when the sun fails to deliver.

The alternatives

Driven by the ever-increasing reliance on batteries, huge amounts of time and money are now being invested in building a successor to lithium-ion.

Scientists at the University of Cambridge claimed a huge breakthrough last year in the development of a “lithium-air” battery that they claim could have 10 times the capacity of today’s lithium-ion technology. By using electrons partially from oxygen in the air, rather than those stored at one end of the battery, it promises enormous advances in capacity – enough to drive an electric car from London to Edinburgh on a single charge.

The idea for lithium-air designs, which the Cambridge scientists describe as the “ultimate battery”, has been around for decades, but traditional lithium-peroxide designs have proven unstable, and incapable of surviving multiple recharges. A new chemical makeup, instead using lithium hydroxide, resulted in fewer chemical reactions draining the battery, and has been re-charged more than 2,000 times.

Researchers from the Argonne National Laboratory in Illinois claimed a separate breakthrough last week, revealing a lithium-superoxide battery that it said solved many of the major problems of other lithium air batteries. Commercial application of these ideas, however, is expected to be years away, possibly at least a decade.

An alternative solution could lie not in better batteries, but better ways of powering them. Intelligent Energy, a British company based in Loughborough, claims to be pioneering the use of hydrogen fuel cells in consumer electronics.

iPhone fitted with Intelligent Energy's fuel cellIntelligent Energy’s technology has made the iPhone last a week  Photo: Intelligent Energy

Henri Winand, the company’s chief executive, says that prototypes of his technology can be used to power a smartphone for a week, or a drone for several hours rather than 30 minutes. Instead of having to be recharged, fuel cells would be interchangeable, swapped in and out when needed. The company is also working with Suzuki on powering fuel cell scooters, and has signed an agreement with an unnamed “emerging” smartphone manufacturer to use its technology.

“We’re not going to have to plan our lives around the plug,” says Winand, who says fuel cell-powered smartphones could be as close as 18 months away.

But for many consumers and companies that rely on battery power, this is not fast enough, or will at least take years to reach mainstream adoption. In the meantime, technology companies are betting on lithium-ion being the technology of choice for the foreseeable future.

Tesla, the electric car company run by the PayPal billionaire Elon Musk, expects to be one of the biggest consumers of batteries in the world. It is spending an estimate $5bn (£3.5bn) on a lithium-ion battery “gigafactory” in the Nevada desert. Many consumer electronics companies, instead of relying on a breakthrough, are working on technologies such as wireless charging, or fast charging, which can bring a battery from empty to 60pc full in half an hour.

Most of the likely candidates to replace our current batteries will still require years of testing and legal approvals to make it into cars or phones. Whoever wins that race, however, will have made one of the breakthroughs of the century.

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