Carbon, Common Materials, a Key Enabler of New Battery Tech

June 11, 2018

Above, properties of graphene, a form of carbon that may make huge improvements possible in key renewable tech like batteries and Solar cells.

Below, a friend sends news of yet more amazing possibilities for energy storage – as battery tech follows a similar performance curve as computer processor speed and memory, as well as solar energy deployment have seen in recent decades.

New Atlas:

Combining the unique strengths of lithium batteries with crazy-fast charging, carbon ultra-capacitors could save a ton of weight and add significant range and power to electric vehicles, according to Nawa Technologies. Based outside Marseilles, this fascinating French startup is working on a new type of battery it believes could offer some huge advantages in the EV space, among many others.

Nawa Technologies’ core product is a new type of carbon ultra-capacitor with a set of remarkable advantages over typical lithium-ion battery cells.

To start with, as a capacitor, its charge and discharge rates are absolutely spectacular compared with batteries – up to 1,000 times faster. We’re talking about charging an entire car battery in a matter of seconds, maybe three times quicker than filling a tank with fossil fuel.

And since there’s no chemical reaction taking place, merely a physical separation of protons and electrons, super-fast charging doesn’t cause any heat build-up or swelling of the battery. That gives the carbon ultra-capacitor an exceptionally long lifetime, up to a million charge cycles.

supportdarksnow

The ultra-capacitor’s monster discharge rate also offers another advantage over lithium batteries. In high-powered EVs, the slow discharge rate of the batteries often means you need to up battery capacity in order to add performance. The Tesla Model S, for example, wouldn’t be able to activate its Ludicrous speed mode with a smaller battery pack, because the slow discharge rates of the batteries would cause a power bottleneck. That’s absolutely not a problem with an ultra-capacitor; these things discharge fast enough to output enormous power with a very small battery.

It’s also very cheap and simple to manufacture, using a process that Nawa Founder and COO Pascal Boulanger describes to us over the phone as “the same process used to create photovoltaic panels. It’s industry proven, highly efficient and cost effective.”

But these remarkable advantages are not the key driver for Boulanger. He believes the carbon ultra-capacitor’s environmental benefits are its biggest calling card.

“For me, the dream comes from the fact that we’re not using lithium, cobalt, rare earth metals,” says Boulanger. “These materials are polluting, and very complicated to extract from the Earth. We’re moving from a society where we extract oil to put in the car, to the same theme, but extracting metals and minerals to put in electric cars. It’s not good, because we’re destroying our planet.

“Nawa’s ultra-capacitors only use carbon and aluminum. Our carbon comes from natural, sustainable sources. We don’t need to mine. When I created Nawa, that was what I wanted to promote: a real, sustainable way. That’s the dream. Building safer and cleaner batteries.”

Could you run a vehicle completely on Nawa’s carbon technology? Yes, says Nawa CEO Ulrik Grape.

“People looking for small cars that are used mainly for small drives, like around city centers, our technology would be perfect,” Grape says. “You can do 50 to 100 kilometers (31 to 62 mi) on our technology alone, and you can recharge the car in less than 10 or 20 seconds. It’s perfect for a fleet of electric cars for sharing.”

But this ultra-capacitor technology does have drawbacks.

For starters, while power density (the amount of power output per unit of weight) is off the charts, energy density doesn’t compete with lithium. An ultra-capacitor will only hold about 25 percent of the energy per unit of weight that a lithium battery can manage, so a car battery with the same sized ultra-capacitor would have only a quarter the range.

Secondly, capacitors suck at long-term energy storage. Leave your car charged up in your garage, and you could expect to leak around 10-20 percent of your energy out each day.

The Nawa team believes that the full potential of the ultra-capacitor, at least in the EV space, becomes unlocked when it’s combined with a lithium battery.

A hybrid lithium/carbon battery system could offer the best of both worlds – long-range continuous driving and long-term power storage thanks to the lithium unit, plus ultra-fast partial charging and extreme power output thanks to the ultra-capacitor.

This kind of hybrid system has another hidden advantage: regenerative braking would become about 450 percent better at recouping energy. Current re-gen systems are forced to throw away the vast majority of energy generated back through the wheels under braking simply because lithium charges so slowly that there’s nowhere to put it all.

“Most of the energy in regenerative braking is lost as heat, maybe 80 percent,” says Grape. “Perhaps 20 percent is recouped. The electric motors are very efficient at generating that power, but the battery just can’t accept the charge rate. If you combine our technology with the lithium battery, we can accept up to 90 percent of that energy.”

Significant news also from MIT, where Daniel Sadoway and his team have been laboring away on large scale batteries meant to store the really significant amounts of energy that could back up power for a whole city.

Short talk here is from 2017, now there is a new breakthrough in the approach he outlines here.

An advantage again, here, is that the so-called “flow” batteries use fairly common, inexpensive, and non-toxic materials.

MIT News Office:

A type of battery first invented nearly five decades ago could catapult to the forefront of energy storage technologies, thanks to a new finding by researchers at MIT. The battery, based on electrodes made of sodium and nickel chloride and using a new type of metal mesh membrane, could be used for grid-scale installations to make intermittent power sources such as wind and solar capable of delivering reliable baseload electricity.

MIT-Battery-Membranes_0

The findings are being reported today in the journal Nature Energy, by a team led by MIT professor Donald Sadoway, postdocs Huayi Yin and Brice Chung, and four others.

Although the basic battery chemistry the team used, based on a liquid sodium electrode material, was first described in 1968, the concept never caught on as a practical approach because of one significant drawback: It required the use of a thin membrane to separate its molten components, and the only known material with the needed properties for that membrane was a brittle and fragile ceramic. These paper-thin membranes made the batteries too easily damaged in real-world operating conditions, so apart from a few specialized industrial applications, the system has never been widely implemented.

But Sadoway and his team took a different approach, realizing that the functions of that membrane could instead be performed by a specially coated metal mesh, a much stronger and more flexible material that could stand up to the rigors of use in industrial-scale storage systems.

“I consider this a breakthrough,” Sadoway says, because for the first time in five decades, this type of battery — whose advantages include cheap, abundant raw materials, very safe operational characteristics, and an ability to go through many charge-discharge cycles without degradation — could finally become practical.

While some companies have continued to make liquid-sodium batteries for specialized uses, “the cost was kept high because of the fragility of the ceramic membranes,” says Sadoway, the John F. Elliott Professor of Materials Chemistry. “Nobody’s really been able to make that process work,” including GE, which spent nearly 10 years working on the technology before abandoning the project.

As Sadoway and his team explored various options for the different components in a molten-metal-based battery, they were surprised by the results of one of their tests using lead compounds. “We opened the cell and found droplets” inside the test chamber, which “would have to have been droplets of molten lead,” he says. But instead of acting as a membrane, as expected, the compound material “was acting as an electrode,” actively taking part in the battery’s electrochemical reaction.

“That really opened our eyes to a completely different technology,” he says. The membrane had performed its role — selectively allowing certain molecules to pass through while blocking others — in an entirely different way, using its electrical properties rather than the typical mechanical sorting based on the sizes of pores in the material.

In the end, after experimenting with various compounds, the team found that an ordinary steel mesh coated with a solution of titanium nitride could perform all the functions of the previously used ceramic membranes, but without the brittleness and fragility. The results could make possible a whole family of inexpensive and durable materials practical for large-scale rechargeable batteries.

The use of the new type of membrane can be applied to a wide variety of molten-electrode battery chemistries, he says, and opens up new avenues for battery design. “The fact that you can build a sodium-sulfur type of battery, or a sodium/nickel-chloride type of battery, without resorting to the use of fragile, brittle ceramic — that changes everything,” he says.

The work could lead to inexpensive batteries large enough to make intermittent, renewable power sources practical for grid-scale storage, and the same underlying technology could have other applications as well, such as for some kinds of metal production, Sadoway says.

Sadoway cautions that such batteries would not be suitable for some major uses, such as cars or phones. Their strong point is in large, fixed installations where cost is paramount, but size and weight are not, such as utility-scale load leveling. In those applications, inexpensive battery technology could potentially enable a much greater percentage of intermittent renewable energy sources to take the place of baseload, always-available power sources, which are now dominated by fossil fuels.

 

 

 

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25 Responses to “Carbon, Common Materials, a Key Enabler of New Battery Tech”

  1. IT Canvass Says:

    Interesting… Thanks for sharing

  2. Kiwiiano Says:

    DO NOT step over the charging cable as that amount of energy passes through it during charging. It may react to the Earth’s magnetic field in a manner not conducive to family planning!!


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