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Want to drive five hundred miles for a dollar? Want your smartphone to render console-quality computer graphics and recharge once a week? Want to be able to use lightweight Google Glass-style wearables for weeks on end without worrying about charging them?
All of these great technology applications are waiting on better battery technology. Battery tech has been growing more slowly than other technologies (like processor speed and computer storage), and is now the long tent pole in a staggering number of industries. There’s good reason to believe that we’re reaching some fundamental limits to current lithium-ion technology, and there are a number of exciting technologies on the horizon. Today we’ll be looking at four of the most promising options.
Better batteries stand to make electric cars practical, untether mobile devices from charge anxiety, and enable whole new classes of lightweight, long-running wearables. Here’s how they’re going to do it:
3. Dual-Carbon Batteries
Besides not being as energy-dense as we might like, there are other serious limitations to existing lithium-ion battery technology – notably charge time, volatility, and degredation.
Lithium ion batteries take time to charge — often several hours, even with the best technology — and, while probably safer than gasoline, they get hot during operation (particularly high-performance batteries like those used in electric vehicles). If heat dissipation isn’t properly managed, the resulting runaway reaction can cause fires or even an explosion.
To make things worse, the charge-discharge cycle of lithium-ion batteries is destructive: after only two hundred and fifty charge-discharge cycles, lithium ion batteries will already have lost about twenty percent of their storage capacity. This is fine for markets like smartphones, where people replace their devices every year or two anyway, but it’s a problem for markets like the electric vehicle, which people would probably like to use for years without having to replace a toxic and expensive battery component.
Now, a company called “Power Japan Plus” thinks it has a solution, in the form of a “dual-carbon” battery. This battery technology replaces the anode and the cathode of the battery (the positive and negative terminals, typically made out of a highly reactive metal like lithium oxide) with plain carbon, which is fairly inert. The result is a battery which doesn’t store dramatically more energy than lithium-ion technology, but does address many of the other limitations of current batteries.
Dual-carbon batteries can charge twenty times faster than lithium ion technology, don’t produce heat during operation, and are much less likely to catch fire. They also degrade much more slowly (they’re good for about three thousand cycles). Because carbon is readily available and chemically harmless, they’re also cheap, relatively non-toxic, and recyclable.
Chris Craney, the Chief Marketing Officer of the company, thinks the batteries will eventually be a big deal for electric cars: speaking to the Atlantic, he said,
“We have ambitious claims […] If there’s an [electric vehicle] company that wants to climb to the Tesla level, we’d be a good company to talk to. […] To be bold, we are confident we are a major solution for the current electric vehicle industry.”
The company plans to begin producing an initial run of batteries this year, for use primarily in medical equipment.
2. Lithium-Air Batteries
Another approach to increasing the density of batteries is to modify the chemistry so that the power-generating reaction draws oxygen from the outside atmosphere (and produces oxygen while recharging), as in the case of lithium-air batteries. This technology is being pursued by IBM among others as an eventual holy grail of battery technology.
By using atmospheric oxygen instead of storing the oxygen in the battery, you can drastically increase the storage density, in theory offering density gains of as much as forty times, compared to conventional lithium cells, leading to electric cars that can travel for thousands of miles on a charge. The existing prototypes beat out current lithium-ion cells by a factor of double. These densities are close to the theoretical limit for what can possibly be achieved by a chemical battery.
This battery technology is some ways off (IBM estimates 5 to 15 years), but in a lot of ways it represents the holy grail of chemical batteries – the best possible density for a given weight. Rechargable lithium-air batteries can rival gasoline for energy density, something unheard of in conventional battery technology. IBM’s page for their research project describes it like this:
Electric cars today typically can travel only about 100 miles on current battery technology, called lithium-ion (LIB). […] Recognizing this, IBM started the Battery 500 project in 2009 to develop a new type of lithium-air battery technology that is expected to improve energy density tenfold, dramatically increasing the amount of energy these batteries can generate and store. Today, IBM researchers have successfully demonstrated the fundamental chemistry of the charge-and-recharge process for lithium-air batteries.
1. Graphene Ultracapacitors
Another, more speculative approach to improving battery performance is to ditch the ‘battery’ part of the idea entirely. An alternative to battery technology is what’s known as capacitors: charged plates, separated by a resistor. Electricity can be stored in the capacitor as an electrostatic field, and then discharged later (think about building up a static charge on your body by petting a cat, and then discharging your body into a doorknob).
Conventional capacitors have serious limits to the amount of charge they can store, as well as how slowly they can release that charge. However, by using materials like graphene, which have enormously high surface areas for their mass and volume, it’s possible to create cells with enormous capacitance and energy densities comparable to conventional batteries.
These ‘ultracapacitors’ wouldn’t degrade on each charge cycle, and would be capable of being charged in seconds. Existing prototypes show no reduction in capacitance over 10,000 charge cycles, and show an energy density comparable to traditional lithium-ion batteries. Future material science improvements could drive those numbers even higher.
In the near term, some insiders report that Tesla is developing a graphene ultracapacitor that could charge in seconds and double the range of their electric cars to 500 miles per charge. Elon Musk, for his part, has mentioned the idea before:
“If I were to make a prediction, I’d think there’s a good chance that it is not batteries, but super-capacitors.”
All of these technologies likely have a role to play, in the near and long term, as we begin to move past the lithium-ion technology that we’ve been using for decades. The transition probably won’t be entirely graceful, or as fast as we might like, but it will enable new applications and technologies that will change the world for decades to come.
What do you think will be the energy technology of the future? Will it be batteries, capacitors, or something else? Share your thoughts in the comments section below!