Super-stable antinomy carbon composite anodes to boost potassium-ion battery storage performance


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Potassium-ion batteries (PIBs) have been considered as promising alternatives to lithium-ion batteries due to the rich natural abundance of potassium (K) and similar redox potential with Li+/Li.

However, due to the large K ion radius and slow reaction dynamics, the previously reported PIB anode materials (carbon-based materials, alloy-based anodes such as tin and antimony, metal oxides, etc.) suffer from a low capacity and fast capacity decay.
In order to achieve a high capacity and excellent cycle stability for K storage process, rational design of the electrode materials and proper selection of the electrolytes should be considered simultaneously.
Recently, two research teams led by Prof. Chunsheng Wang and Prof. Michael R. Zachariah from the University of Maryland, College Park, have designed and fabricated a novel antimony (Sb) carbon composite PIB anode via a facile and scalable electrospray-assisted strategy and found that this anode delivered super high specific capacities as well as cycling stability in a highly concentrated electrolyte (4M KTFSI/EC+DEC).
This work has been published in Energy and Environmental Science (“Super Stable Antimony-carbon composite anodes for potassium-ion batteries”).

 

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Figure 1. Schematic illustration of electrospray-assisted strategy for fabricating antimony @carbon sphere network electrode materials. (© Royal Society of Chemistry)
We have successfully fabricated a novel antimony carbon composite with small Sb nanoparticles uniformly confined in the carbon sphere network (Sb@CSN) via a facile and scalable electrospray-assisted strategy.
Such a unique nanostructure can effectively mitigate the deleteriously mechanical damage from large volume changes and provide a highly conductive framework for fast electron transport during alloy/de-alloy cycling process.
Alongside the novel structural design of the anode material, formation of a robust solid-electrolyte-interphase (SEI) on the anode is crucially important to achieve its long-term cycling stability.
The formation of a robust SEI on the anode material is determined by both the surface chemistries of active electrode materials as well as electrolyte compositions such as salt anion types and concentrations.
Therefore, designing a proper electrolyte is extremely important for the anode to achieve a high cycling stability.
In our study, we have for the first time developed a stable and safe electrolyte of highly concentrated 4M KTFSI/EC+DEC for PIBs to promote the formation of a stable and robust KF-rich SEI layer on an Sb@CSN anode, which guarantees stable electrochemical alloy/de-alloy reaction dynamics during long-time cycling process.
Cycling performance of antimony carbon sphere network electrode materials
Figure 2. Cycling performance of antimony carbon sphere network electrode materials at 200mA/g current density in the highly concentrated electrolyte (4M KTFSI/EC+DEC). (© Royal Society of Chemistry)
In the optimized 4M KTFSI/EC+DEC electrolyte, the Sb@CSN composite delivers excellent reversible capacity of 551 mAh/g at 100 mA/g over 100 cycles with a capacity decay of 0.06% per cycle from the 10st to 100th cycling and 504 mAh/g even at 200 mA/g after 220 cycling. This demonstrates the best electrochemical performances with the highest capacity and longest cycle life when compared with all K-ion batteries anodes reported to date.
The electrochemical reaction mechanism was further revealed by density functional theory (DTF) calculation to support such excellent Potassium-storage properties.
Capacity comparison of Sb@CSN anode with previous reported anodes in potassium ion batteries
Figure 3. Capacity comparison of Sb@CSN anode with previous reported anodes in potassium ion batteries. (© Royal Society of Chemistry)
In conclusion, these outstanding performances should be attributed to the novel nanostructure of Sb nanoparticles uniformly encapsulated into conductive carbon network and the formation of a more stable and robust KF-rich SEI layer on Sb@CSN in the optimized 4M KTFSI electrolyte.
These encouraging results will significantly promote the deep understanding of the fundamental electrochemistry in Potassium-ion batteries as well as rational development of efficient electrolyte systems for next generation high-performance Potassium-ion batteries.
Yong Yang, Research Associate, Prof. Zachariah Research Group, Department of Chemical and Environmental Engineering, University of California, Riverside
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Cornell University: Pore size influences nature of complex nanostructures – Materials for energy storage, biochemical sensors and electronics


The mere presence of void or empty spaces in porous two-dimensional molecules and materials leads to markedly different van der Waals interactions across a range of distances. Credit: Yan Yang and Robert DiStasio

Building at the nanoscale is not like building a house. Scientists often start with two-dimensional molecular layers and combine them to form complex three-dimensional architectures.

And instead of nails and screws, these structures are joined together by the attractive van der Waals forces that exist between objects at the nanoscale.

Van der Waals forces are critical in constructing  for energy storage, biochemical sensors and electronics, although they are weak when compared to chemical bonds. They also play a crucial role in , determining which drugs bind to the active sites in proteins.

In new research that could help inform development of new materials, Cornell chemists have found that the empty space (“pores”) present in two-dimensional molecular building blocks fundamentally changes the strength of these van der Waals forces, and can potentially alter the assembly of sophisticated nanostructures.

The findings represent an unexplored avenue toward governing the self-assembly of complex nanostructures from porous two-dimensional building blocks.

“We hope that a more complete understanding of these forces will aid in the discovery and development of novel materials with diverse functionalities, targeted properties, and potentially novel applications,” said Robert A. DiStasio Jr., assistant professor of chemistry in the College of Arts and Sciences.

In a paper titled “Influence of Pore Size on the van der Waals Interaction in Two-Dimensional Molecules and Materials,” published Jan. 14 in Physical Review Letters, DiStasio, graduate student Yan Yang and postdoctoral associate Ka Un Lao describe a series of mathematical models that address the question of how void space fundamentally affects the attractive physical forces which occur over nanoscale distances.

In three prototypical model systems, the researchers found that particular pore sizes lead to unexpected behavior in the  that govern van der Waals forces.

Further, they write, this behavior “can be tuned by varying the relative size and shape of these void spaces … [providing] new insight into the self-assembly and design of complex nanostructures.”

While strong covalent bonds are responsible for the formation of two-dimensional molecular layers, van der Waals interactions provide the main attractive  between the layers. As such, van der Waals forces are largely responsible for the self-assembly of the complex three-dimensional nanostructures that make up many of the advanced materials in use today.

The researchers demonstrated their findings with numerous two-dimensional systems, including covalent organic frameworks, which are endowed with adjustable and potentially very large pores.

“I am surprised that the complicated relationship between void space and van der Waals forces could be rationalized through such simple models,” said Yang. “In the same breath, I am really excited about our findings, as even  in the van der Waals forces can markedly impact the properties of molecules and materials.”

Explore further: Researchers refute textbook knowledge in molecular interactions

More information: Yan Yang et al, Influence of Pore Size on the van der Waals Interaction in Two-Dimensional Molecules and Materials, Physical Review Letters (2019).  DOI: 10.1103/PhysRevLett.122.026001 

Renewable Energy Trends and Updates for 2019: TEDx Presents 5 ‘Under 30′ Entrepreneurs’ Visions


 

 

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Visions For the Future of Renewable Energy

2019 is an exciting year for renewable energy. More and more countries and cities are adopting ambitious renewable energy targets and the technology is evolving rapidly. Many of these technologies, such as microgrids and energy storage, could become mainstream technology in the coming years. At this speed of innovation, it is difficult to keep track of all the changes!

This selection of TED Talks covers some of the most fascinating and promising energy topics for 2019. Be sure to read the 2018 Climate Change Overview and list of Energy Trends To Watch In 2019 before diving into these talks to better understand the impact of these new developments.

1. Accelerating The Shift To Clean Energy, Bill Nussey

 

Topic: Building local, consumer-driven electricity markets, such as the Brooklyn Microgrid, with renewable energy resources. (2017).

Nussey is an entrepreneur, investor, speaker, clean tech CEO and founder of the Freeing Energy Project.

“Solar and batteries are governed by something called Swanson‘s law, which states the more product you manufacture, the cheaper it gets. If we want to unleash society’s most powerful force for change, the irresistible economics of a lower price, we just need to make more and more solar panels and batteries. This is where you come in.  For the first time in energy history, each of us can play a role in creating the future. All we have to do is embrace clean, local energy ourselves. Install solar panels. Purchase community solar. Buy an electric vehicle to drive up the battery volumes. Do business with companies powered by clean energy. Every little thing we do adds up.”

2. Batteries Not Included, Marek Kubik

Topic: How energy storage technologies are transforming our approach to electricity generation with renewables. (2018).

Kubik is an energy and sustainability futurist, Forbes 30 Under 30 Honouree and TEDx speaker.

“Solar and wind are already cost-competitive today. The cost of these technologies has fallen to a point where, in many countries, they are already the cheapest forms of electricity generation. And that trend is set to continue.”

3. Ground Zero For Global Energy Transition, Justin Locke

Topic: The role of leadership that small islands are taking in developing sustainable energy solutions. (2017).

Locke is a writer and speaker on sustainable energy and the director for the Islands Energy Program at the Rocky Mountain Institute. (See also: Electric Vehicles in Barbados).

“Islands have been determined as victims of colonization, occupation and now climate change. But now they are flipping that script and actually providing the solutions to the world’s most difficult challenge: how to combat climate change.”

global energy storage ii battery_storage_illustration_xl_721_420_80_s_c1Read More: “5 Predictions for the Global Energy Storage Market in 2019” from Green Tech Media

4. A Printable, Flexible, Organic Solar Cell, Hannah Bürckstümmer

Topic: Efficient, flexible organic solar cells that can be printed in any shape to allow the facades of buildings to capture solar from every exposed surface. (2017).

Bürckstümmer has a background in chemistry and a curiosity about our environment, which she has translated into research into third-generation solar cells and work on the strategy and marketing for organic photovoltaics.

“This is pointing towards a future where buildings are no longer energy consumers, but energy providers. I want to see solar cells seamlessly integrated into our building shells to be both resource-efficient and a pleasure to look at. To exploit the potential of all facades and other areas, organic photovoltaics can offer a significant contribution, and they can be made in any form architects and planners will want them to.”

5. The Thrilling Potential For Off-Grid Solar Energy, Amar Inamdar

Topic: How the factors of distributed generation- lower costs, infrastructure and decentralization- are revolutionizing the energy market, to the benefit of the environment. (2017).

Inamdar works with businesses and entrepreneurs to imagine, create and grow markets that address our biggest social and environmental challenges.

“We aspire towards energy access for everybody, and we aspire towards a fully-functioning low-carbon economy. And we’re getting to the point where we’re seeing the fully-functioning low-carbon economy is not just about getting people onto the grid, it’s about getting people onto electricity and doing it in a way that’s really dignified.”
What’s Next?
To learn more about the latest energy trends, you should read the 2018 Climate Change Overview and list of Energy Trends To Watch In 2019. Stay tuned for another selection of TED Talks in February with a focus on the latest science and action combating global climate change. Presented by James Ellsmoor is a Forbes 30 Under 30 entrepreneur.

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Lithium ion Battery Tech gets a ‘Cool’ rival: Frozen Liquid Air – Could LAES ‘de-throne’ the King?


schematic-of-liquid-air-energy-storage-laes-system

In a bid to help scale renewable energy, many companies are working on new ways to store energy long-term. But the plain old battery is still king. Can ultra-cold liquid air make all the difference?

Elon Musk’s Tesla took less than 100 days to install its Hornsdale Power Reserve – the world’s largest lithium ion battery – in dusty, sunny South Australia, following a Twitter bet. UK-based Highview Power has been a bit slower than that. After years of delays, its Liquid Air Energy Storage (LAES) plant near Manchester has come online.

It’s the world’s first grid-scale liquid air energy storage plant – and with off-the-shelf components, it’s relatively easy and cheap to build and to scale. Air is cooled down, made liquid, and stored in tanks for weeks until you need electricity again. Sounds pretty cool, doesn’t it?

While it’s certainly a moment of success for alternative energy storage, don’t break out the confetti yet: lithium ion isn’t about to give up its crown, says Dan Finn-Foley, a senior analyst at GTM Research. In the US alone, li-ion battery technology accounts for more than 95 per cent of annual storage deployments. But batteries, even the most efficient ones, fail to store energy for longer than a few hours.

So where does it leave solar and wind power, with their need to smooth out the supply peaks and troughs?

“Alternative energy storage could be a holy grail for the grid, a missing link that could get us towards renewables much faster,” explains Ravi Manghani, the director of the energy storage section of GTM Research.

One thing is certain: without reliable energy storage technology, the world will struggle to wean itself off dirty coal and other fossil fuels. If an economy and society wants to rely on renewables on a massive scale, it needs a backup solution. Renewables are growing fast – last year, 29 per cent of all electricity in the UK was generated by renewable energy plants; in Germany, it was 33 per cent.

But the sun doesn’t shine at night, and wind doesn’t always blow. Right now, the storage market is dominated by lithium ion battery technology, but despite Tesla’s worldwide total of one gigawatt-hour of energy storage, the available batteries can last about eight hours tops. “We absolutely must install multiple days worth of energy storage – we can’t get away with four to six hours only,” says Manghani.

Storing electricity for longer

Hornsdale Power Reserve 100 MW storage system can provide 129 megawatt-hours of electricity and is connected to the Hornsdale Wind Farm. Its primary aim is to increase grid stability during system contingencies events like extremely hot summer afternoons, or when a large gas plant will trip – it improves the grid’s ability to cope with small blips in energy generation, which typically means replacing about one to one and half hour of energy supply.

“It’s designed to handle very short duration contingency needs,” says Finn-Foley. That’s why batteries simply can’t provide peak power, or compete with and replace so-called ‘peaker’ plants – power plants like natural gas power stations that are only switched on to fill the gap at times of peak energy demand. They also can’t help extend the use of solar power to later in the day. “You’ll need 10 to 12 hours of continuous discharge duration, which means you’ll need four times the battery or more,” says Finn-Foley.

That’s where alternative energy storage technologies could change things.

Currently, the best long-duration energy storage solutions are thermal storage, pumped hydro, compressed air energy storage – and the newest kid on the block, liquid air energy storage. There are also alternative battery technologies such as flow batteries, which researchers believe may one day scale up to discharge energy for longer than lithium ion.

At the end of the day, though, it all comes down to cost. And developing and operating novel tech is not cheap. The cost of lithium ion batteries, meanwhile, keeps on plummeting, thanks to the ever-surging demand for consumer electronics and electric cars, with all the giga and megafactories mushrooming around the globe. Over the past few years, li-ion battery prices dropped by more than 60 per cent – and are expected to fall by another 40 per cent by 2022.

These cost drops are impressive – but while batteries are good for providing power over short timescales, they quickly get very expensive for storing large amounts of energy over hours and days.

What is liquid air energy storage?

Enter LAES. First dreamt up in the 1970s in the UK and then toyed with in the 1980s and 90s by Hitachi and Mitsubishi (without any proper pilot plants though), this tech has the potential to scale up at low cost, says professor Yulong Ding at the University of Birmingham, who together with Highview developed the technology.

liquid air energy ii

LAES works by using electricity from the grid to cool atmospheric air until it liquifies, and then storing it in big tanks at low pressure at –196C – at a fraction of the air’s original volume. “The working principle is quite similar to a domestic fridge – just the temperature and pressure ranges are different,” says Ding. The air can stay in the tanks for weeks and even months, dissipating slowly – and the better the insulation, the slower it will vanish. “It can easily be kept in tanks for about two months,” adds Ding.

When you need to generate electricity, you just have to heat the air to ambient temperature. In the process it will expand a whopping 700 times, creating a lot of air pressure that can be used to spin a turbine in the same way that, say, steam would in conventional generators – and produce electricity.

Because it’s so similar to a traditional fridge, the individual components of LAES for cooling, storing, and re-pressurising gases can be bought quite cheaply off the shelf. “These are well-understood, decades and centuries-old processes that are highly cost-efficient,” says Finn-Foley. The only novel bit here, says Ding, is the integration of the different parts in the most-optimised way.

LAES is not that efficient, though: Tesla’s battery in Australia is 88 per cent efficient, while LAES is 60 to 70 per cent, says Manghani. But as batteries can only store energy for a few hours, if they need to supply energy for longer, they quickly get very costly.

LAES also cannot respond to grid signals in a matter of milliseconds like batteries do. On the upside, the liquid air project can provide energy in bulk, around a day’s worth of it (although the pilot can store just 5 MW of electricity – enough to power roughly 5,000 homes for about three hours; on a commercial scale, Manchester’s LAES plant could have the capacity of 50 MW).

Still, as the liquid air energy storage is so cheap and can scale easily, it could, potentially, fill a crucial gap in the successful energy ecosystem geared towards renewables. Why, then, is it just the UK looking into it? Jonathan Radcliffe, an energy researcher at the University of Birmingham, has a simple answer: because of the UK’s ambitious plans for electricity generation from offshore wind in the 2020s. Also, he adds, “as an island, we have fewer connections to other electricity networks that could help balance supply and demand”.

Manghani is even more prosaic: the world isn’t ready for LAES just yet. Even at the scale of current use of renewables in countries like Germany and Australia, “there is no market out there that needs such longer duration of storage solutions,” he says – experimental plants like LAES are looking for a problem that doesn’t yet exist. But in a decade from now, once solar panel arrays and wind turbines produce more than 60 or 70 per cent of our energy, long-duration storage will be crucial. And we can’t wait a decade to start finding a viable solution, says Manghani – we have to get ready now.

De-Throning the king?

Highview claims that overall, LAES plants will be cheaper than lithium ion; if that’s confirmed at scale: “I expect the technology to go global quickly,” says Finn-Foley. But first, it has to start competing in multiple markets and applications, and existing regulations, as well as incentives to invest in energy storage, are a challenge.

laes iii application-comparison-for-various-energy-storage-technologies-with-the-addition-of-ptes

The LAES plant “will need to operate for some time to demonstrate that they have truly worked out the kinks, says Finn-Foley. It also has to prove viability, which is tricky for a project that is supposed to run for decades. “Batteries degrade and must be replaced – but proving a forty-year lifetime is hard to do until you’ve run it for 40 years,” he adds.

But in the end of the day, alternative technologies aren’t trying to usurp li-ion’s throne, but “carve out their own kingdom, with applications and use cases that they think they can do better,” he says. “So far they have been unsuccessful, but a pilot project proving cost-effectiveness is a crucial step.” For the next five years though, he says, “lithium ion will keep the crown”.

 

Volkswagen is Rolling Out Mobile EV Charging Stations – Charge Your EV in as Little as 17 Minutes


“Charge Up in as little as 17 minutes.”

 

To say Volkswagen has ambitious plans for electric vehicles may be an understatement.

The automaker projects it will produce 15 million vehicles on its new MEB platform in the first wave of its EV assault, and it plans to invest 9 billion euros in the new VW I.D. familythrough 2023.

The marque will have 20 electric models in its lineup by 2025, up from just two entries now. To support this barrage of new EVs, Volkswagen is getting ready to introduce mobile quick-charging stations.

The charging columns are based on the battery pack used with the automaker’s MEB platform.

These stations can be set up in public parking lots, at a company building, or at large events, then removed when no longer needed. VW says the charging process takes an average of 17 minutes.

With a battery storage capacity of 360 kilowatt-hours, each station can charge up to 15 electric vehicles before themselves needed to be recharged.

Volkswagen Nails Down $25 Billion in Batteries for EV’s

As many as four vehicles can be charged at the same time, two with DC quick-charging connections and two with AC connections.

Charging stations that have depleted their energy storage would be exchanged for full ones.

When linked up to a power supply, however, the mobile station can be recharged constantly. The charging stations can be juiced up via solar or wind energy, providing C02 neutrality.

Furthermore, VW suggests reusing batteries from electric vehicles to power the stations.

Watch a Short YouTube Video on NextGen Nano-Enabled Batteries and Super Capacitors

 

Promising New Battery Technology – Disordered Magnesium Crystals – Could make Batteries that are Smaller and that store More Energy – Longer Lasting Phones and EV Batteries


Magneseum Battery Nano 5c1966937fa4cTiny, disordered particles of magnesium chromium oxide may hold the key to new magnesium battery energy storage technology. Credit: UCL

 

Tiny, disordered particles of magnesium chromium oxide may hold the key to new magnesium battery energy storage technology, which could possess increased capacity compared to conventional lithium-ion batteries, find UCL and University of Illinois at Chicago researchers.

The study, published today in Nanoscale, reports a new, scalable method for making a material that can reversibly store  at high-voltage, the defining feature of a cathode.

While it is at an , the researchers say it is a significant development in moving towards -based batteries. To date, very few inorganic materials have shown reversible magnesium removal and insertion, which is key for the magnesium battery to function.

“Lithium-ion technology is reaching the boundary of its capability, so it’s important to look for other chemistries that will allow us to build batteries with a bigger storage capacity and a slimmer design,” said co-lead author, Dr. Ian Johnson (UCL Chemistry).

“Magnesium battery technology has been championed as a possible solution to provide longer-lasting phone and electric car batteries, but getting a practical material to use as a cathode has been a challenge.”

One factor limiting  is the anode. Low-capacity carbon anodes have to be used in lithium-ion batteries for safety reasons, as the use of pure lithium metal anodes can cause dangerous short circuits and fires.

In contrast, magnesium metal anodes are much safer, so partnering magnesium metal with a functioning cathode material would make a battery smaller and store more energy.

Previous research using computational models predicted that magnesium chromium oxide (MgCr2O4) could be a promising candidate for Mg battery cathodes.

Inspired by this work, UCL researchers produced a ~5 nm, disordered magnesium chromium oxide material in a very rapid and relatively low temperature reaction.

Collaborators at the University of Illinois at Chicago then compared its magnesium activity with a conventional, ordered magnesium chromium oxide material ~7 nm wide.

They used a range of different techniques including X-ray diffraction, X-ray absorption spectroscopy and cutting-edge electrochemical methods to see the structural and chemical changes when the two materials were tested for magnesium activity in a cell.

The two types of crystals behaved very differently, with the disordered particles displaying reversible magnesium extraction and insertion, compared to the absence of such activity in larger, ordered crystals.

“This suggests the future of batteries might lie in disordered and unconventional structures, which is an exciting prospect and one we’ve not explored before as usually disorder gives rise to issues in battery materials. It highlights the importance of seeing if other structurally defective materials might give further opportunities for reversible battery chemistry” explained Professor Jawwad Darr (UCL Chemistry).

“We see increasing the surface area and including disorder in the crystal structure offers novel avenues for important chemistry to take place compared to ordered crystals.

Conventionally, order is desired to provide clear diffusion pathways, allowing cells to be charged and discharged easily—but what we’ve seen suggests that a disordered structure introduces new, accessible diffusion pathways that need to be further investigated,” said Professor Jordi Cabana (University of Illinois at Chicago).

These results are the product of an exciting new collaboration between UK and US researchers. UCL and the University of Illinois at Chicago intend to expand their studies to other disordered, high  , to enable further gains in magnesium storage capability and develop a practical magnesium .

 Explore further: Research overcomes major technical obstacles in magnesium-metal batteries

More information: Linhua Hu et al, Tailoring the Electrochemical Activity of Magnesium Chromium Oxide Towards Mg Batteries Through Control of Size and Crystal Structure, Nanoscale (2018). DOI: 10.1039/C8NR08347A

 

A Better Battery from Biology? Osaka University Researchers Publish Promising Results


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Figure 1: Structure of the newly developed ionic crystal. The pathway in which the ions can travel is highlighted in yellow. (Image: Osaka University)

A research team at Osaka University has reported a new advance in the design of materials for use in rechargeable batteries, under high humidity conditions. Using inspiration from living cells that can block smaller particles but let larger particles pass through, the researchers were able to create a material with highly mobile potassium ions that can easily migrate in response to electric fields (Chemical Science“Mobility of hydrated alkali metal ions in metallosupramolecular ionic crystals”).

This work may help make rechargeable batteries safe and inexpensive enough to drastically reduce the cost of electric cars and portable consumer electronics.
h27 map english
Link to Osaka University’s Joint Research Programs
Rechargeable lithium-ion batteries are widely used in laptops, cell phones, and even electric and hybrid cars. Unfortunately, these batteries are expensive, and have even been known to burst into flames on occasion.
New materials that do not use lithium could reduce the cost and improve the safety of these batteries, and have the potential to greatly accelerate the adoption of energy-efficient electric cars. Both sodium and potassium ions are potential candidates that can be used to replace lithium, as they are cheap and in high supply.
However, sodium and potassium ions are much larger ions than lithium, so they move sluggishly through most materials. These positive ions are further slowed by the strong attractive forces to the negative charges in crystalline materials.
“Potassium ions possess low mobility in the solid state due to their large size, which is a disadvantage for constructing batteries,” explains corresponding author Takumi Konno.
To solve this problem, the researchers used the same mechanism your cells employ to allow the large potassium ions to pass through their membranes while simultaneously keeping out smaller particles. Living systems achieve this seemingly impossible feat by considering not just the ion themselves, but also the surrounding water molecules, called the “hydration layer,” that are attracted to the ion’s positive charge.
In fact, the smaller the ion, the larger and more tightly bound its associated hydration layer will be. Specialized potassium channels in cell membranes are just the right size to allow hydrated potassium ions to pass through, but block the large hydration layers of smaller ions.
The researchers developed an ionic crystal using rhodium, zinc, and oxygen atoms. Just as with the selective biological channels, the mobility of the ions in the crystal was found to be higher for the bigger potassium ions, compared with the smaller lithium ions.
In fact, the potassium ions moved so easily, the crystal was classified as a “superionic conductor.” The researchers found that the current material had the largest hydrated potassium ion mobility ever seen to date.
id51550_1
 

Figure 2: Conductivities of lithium (Li , red), sodium (Na , green), and potassium (K , blue) ions inside the crystal at different temperatures. The conductivities increase even as the sizes of the ions increase. (Image: Osaka University)

“Remarkably, the crystal exhibited a particularly high ion conductivity due to the fast migration of hydrated potassium ions in the crystal lattice” lead author Nobuto Yoshinari says. “Such superionic conductivity of hydrated potassium ions in the solid state is unprecedented, and may lead to both safer and cheaper rechargeable batteries.”
Source: Osaka University

Scientists develop Lithium Metal batteries that charge faster, last longer with 10X times more energy by volume than Li-Ion Batteries – BIG potential for Our EV / AV Future


 

October 25, 2018

Rice University scientists are counting on films of carbon nanotubes to make high-powered, fast-charging lithium metal batteries a logical replacement for common lithium-ion batteries.

The Rice lab of chemist James Tour showed thin nanotube films effectively stop dendrites that grow naturally from unprotected lithium metal anodes in batteries. Over time, these tentacle-like dendrites can pierce the battery’s electrolyte core and reach the cathode, causing the battery to fail.

That problem has both dampened the use of lithium metal in commercial applications and encouraged researchers worldwide to solve it.

img_0837-1Rice University graduate student Gladys López-Silva holds a lithium metal anode with a film of carbon nanotubes. Once the film is attached, it becomes infiltrated by lithium ions and turns red. Photo by Jeff Fitlow

Lithium metal charges much faster and holds about 10 times more energy by volume than the lithium-ion electrodes found in just about every electronic device, including cellphones and electric cars.

 

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MIT NEWS: Read More About Lithium Metal Batteries

“One of the ways to slow dendrites in lithium-ion batteries is to limit how fast they charge,” Tour said. “People don’t like that. They want to be able to charge their batteries quickly.”

The Rice team’s answer, detailed in Advanced Materials, is simple, inexpensive and highly effective at stopping dendrite growth, Tour said.

“What we’ve done turns out to be really easy,” he said. “You just coat a lithium metal foil with a multiwalled carbon nanotube film. The lithium dopes the nanotube film, which turns from black to red, and the film in turn diffuses the lithium ions.”

“Physical contact with lithium metal reduces the nanotube film, but balances it by adding lithium ions,” said Rice postdoctoral researcher Rodrigo Salvatierra, co-lead author of the paper with graduate student Gladys López-Silva. “The ions distribute themselves throughout the nanotube film.”

img_0835An illustration shows how lithium metal anodes developed at Rice University are protected from dendrite growth by a film of carbon nanotubes. Courtesy of the Tour Group

When the battery is in use, the film discharges stored ions and the underlying lithium anode refills it, maintaining the film’s ability to stop dendrite growth.

The tangled-nanotube film effectively quenched dendrites over 580 charge/discharge cycles of a test battery with a sulfurized-carbon cathode the lab developed in previous experiments.

The researchers reported the full lithium metal cells retained 99.8 percent of their coulombic efficiency, the measure of how well electrons move within an electrochemical system.

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Rice University scientists have discovered that a film of multiwalled carbon nanotubes quenches the growth of dendrites in lithium metal-based batteries. Courtesy of the Tour Group

Co-authors of the paper are Rice alumni Almaz Jalilov of the King Fahd University of Petroleum and Minerals, Saudi Arabia; Jongwon Yoon, a senior researcher at the Korea Basic Science Institute; and Gang Wu, an instructor, and Ah-Lim Tsai, a professor of hematology, both at the McGovern Medical School at the University of Texas Health Science Center at Houston.

Tour is the T.T. and W.F. Chao Chair in Chemistry as well as a professor of computer science and of materials science and nanoengineering at Rice.

The research was supported by the Air Force Office of Scientific Research, the National Institutes of Health, the National Council of Science and Technology, Mexico; the National Council for Scientific and Technological Development, Ministry of Science, Technology and Innovation and Coordination for the Improvement of Higher Education Personnel, Brazil; and Celgard, LLC.

1028_DENDRITE-5-rn-18fsg2wRice University chemist James Tour, left, graduate student Gladys López-Silva and postdoctoral researcher Rodrigo Salvatierra use a film of carbon nanotubes to prevent dendrite growth in lithium metal batteries, which charge faster and hold more power than current lithium-ion batteries. Photo by Jeff Fitlow.

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What’s Next: Beyond the lithium-ion battery


PWENERGYNov18Provoost_IMEC-635x357Drive for innovation: Electric vehicles are a major target for R&D on novel battery materials. (Image courtesy: imec)
31 Oct 2018
Note to Readers: This article first appeared in the 2018 Physics World Focus on Energy Technologies Engineering a sustainable, electrified future means developing battery materials with properties that surpass those found in current technologies.

The batteries we depend on for our mobile phones and computers are based on a technology that is more than a quarter-century old. Rechargeable lithium-ion (Li-ion) batteries were first introduced in 1991, and their appearance heralded a revolution in consumer electronics. From then on, we could pack enough energy in a small volume to start engineering a whole panoply of portable electronic devices – devices that have given us much more flexibility and comfort in our lives and jobs.

In recent years, Li-ion batteries have also become a staple solution in efforts to solve the interlinked conundrums of climate change and renewable energy. Increasingly, they are being used to power electric vehicles and as the principal components of home-based devices that store energy generated from renewable sources, helping to balance an increasingly diverse and smart electrical grid. The technology has improved too: over the past two and a half decades, battery experts have succeeded in making Li-ion batteries 5–10% more efficient each year, just by further optimizing the existing architecture.

Ultimately, though, getting from where we are now to a truly carbon-free economy will require better-performing batteries than today’s (or even tomorrow’s) Li-ion technology can deliver. In electric vehicles, for example, a key consideration is for batteries to be as small and lightweight as possible.

 

Achieving that goal calls for energy densities that are much higher than the 300 Wh/kg and 800 Wh/L which are seen as the practical limits for today’s Li-ion technology.

Another issue holding back the adoption of electric vehicles is cost, which is currently still around 300–200 $/kWh, although that is widely projected to go below 100 $/kWh by 2025 or even earlier. The time required to recharge a battery pack – still in the range of a few hours – will also have to come down, and as batteries move into economically critical applications such as grid storage and grid balancing, very long lifetimes (a decade or more) will become a key consideration too.

There is still some room left to improve existing Li-ion technology, but not enough to meet future requirements. Instead, the process of battery innovation needs a step change: materials-science breakthroughs, new electrode chemistries and architectures that have much higher energy densities, new electrolytes that can deliver the necessary high conductivity – all in a battery that remains safe and is long-lasting as well as economical and sustainable to produce.

Lithium magic

To appreciate why this is such a challenge, it helps to understand the basic architecture of existing batteries. Rechargeable Li-ion batteries are made up of one or more cells, each of which is a small chemical factory essentially consisting of two electrodes with an electrolyte in between. When the electrodes are connected (for example with a wire via a lamp), an electrochemical process begins. In the anode, electrons and lithium ions are separated, and the electrons buzz through the wire and light up the lamp. Meanwhile, the positively-charged lithium ions move through the electrolyte to the cathode. There, electrons and Li-ions combine again, but in a lower energy state than before.

The beauty of rechargeable batteries is that these processes can be reversed, returning lithium ions to the anode and restoring the energy states and the original difference in electrical potential between the electrodes. Lithium ions are well suited for this task. Lithium is not only the lightest metal in the periodic table, but also the most reactive and will most easily part with its electrons. It has been chosen as the basis for rechargeable batteries precisely because it can do the most work with the least mass and the fewest chemical complications. More specifically, in batteries using lithium, it is possible to make the electric potential difference between anodes and cathodes higher than is possible with other materials.

To date, therefore, the main challenge for battery scientists has been to find chemical compositions of electrodes and electrolyte that will let the lithium ions do their magic in the best possible way: electrodes that can pack in as many lithium ions as possible while setting up as high an electrical potential difference as possible; and an electrolyte that lets lithium ions flow as quickly as possible back and forth between the anode and cathode.

Seeking a solid electrolyte

The electrolyte in most batteries is a liquid. This allows the electrolyte not only to fill the space between the electrodes but also to soak them, completely filling all voids and spaces and providing as much contact as possible between the electrodes and the electrolyte. To complete the picture, a porous membrane is added between the electrodes. This inhibits electrical contact between the electrodes and prevents finger like outgrowths of lithium from touching and short-circuiting the battery.
For all the advantages of liquid electrolytes, though, scientists have long sought to develop solid alternatives. A solid electrolyte material would eliminate several issues at the same time. Most importantly, it would replace the membrane, allowing the electrodes to be placed much closer together without touching, thereby, making the battery more compact and boosting its energy density. A solid electrolyte would also make batteries stronger, potentially meaning that the amount of protective and structural casing could be cut without compromising on safety.

Unfortunately, the solid electrolytes proposed so far have generally fallen short in one way or another. In particular, they lack the necessary conductivity (expressed in milli-Siemens per centimetre, or mS/cm). Unsurprisingly, ions tend not to move as freely through a solid as they do through a liquid. That reduces both the speed at which a battery can charge and, conversely, the quantity of power it can release in a given time.

Scientists at imec – one of Europe’s premier nanotechnology R&D centres, and a partner in the EnergyVille consortium for sustainable energy and intelligent energy systems research – recently came up with a potential solution. The new material is a nanoporous oxide mix filled with ionic compounds and other additives, with the pores giving it a surface area of about 500 m2/mL – “comparable to an Olympic swimming pool folded into a shot glass,” says Philippe Vereecken, imec’s head of battery research. Because ions move faster along the pores’ surface than in the middle of a lithium salt electrolyte, he explains, this large surface area amplifies the ionic conductivity of the nanoengineered solid. The result is a material with a conductivity of 10 mS/cm at room temperature – equivalent to today’s liquid electrolytes.

Using this new electrolyte material, imec’s engineers have built a cell prototype using standard available electrodes: LFP (LiFePO4) for the cathode and LTO (Li4Ti5O12) for the anode. While charging, the new cell reached 80% of its capacity in one hour, which is already comparable to a similar cell made with a liquid electrolyte. Vereecken adds that the team hopes for even better results with future devices. “Computations show that the new material might even be engineered to sustain conductivities of up to 100 mS/cm,” he says.

Meanwhile, back at the electrode

Electrodes are conventionally made from sintered and compressed powders. Combining these with a solid electrolyte would normally entail mixing the electrode as a powder with the electrolyte also in powder form, and then compressing the result for a maximum contact. But even then, there will always remain pores and voids that are not filled and the contact surface will be much smaller than is possible with a liquid electrolyte that fully soaks the electrode.

Lithium-sulphur is a promising material that could store more energy than today’s technology allows

Lith Sulfur Batts c5cs00410a-f2_hi-res

Imec’s new nano-composite material avoids this problem because it is actually applied as a liquid, via wet chemical coating, and only afterwards converted into a solid. That way it can impregnate dense powder electrodes, filling all cavities and making maximum contact just as a liquid electrolyte would. Another benefit is that even as a solid, the material remains somewhat elastic, which is essential as some electrodes expand and contract during battery charging and discharging. A final advantage is that because the solid material can be applied via a wet precursor, it is compatible with current Li-ion battery fabrication processes – something that Vereecken says is “quite important for the battery manufacturers” because otherwise more “disruptive” fabrication processes would have to be put in place.

To arrive at the energy densities required to give electric vehicles a long driving range, though, still more changes are needed. One possibility is to make the particles in the electrode powders smaller, so that they can be packed more densely. This would produce a larger contact surface with the electrolyte per volume, improving the energy density and charging rate of the cell. There is a catch, though: while a larger contact surface results in more ions being created and changing sides within the battery, it also gives more way for unwanted reactions that will degrade the battery’s materials and shorten its lifetime. “To improve the stability,” says Vereecken, “imec’s experts work on a solution where they coat all particles with an ultrathin buffer layer.” The challenge, he says, is to make these layers both chemically inert and highly conductive.

Introducing new materials

By combining solid electrolytes with thicker electrodes made from smaller particles, it may be possible to produce batteries with energy densities that exceed the current maximum of around 800 Wh/L. These batteries could also charge in 30 minutes or less. But to extend the energy density even further, to 1000 Wh/L and beyond, a worldwide effort is on to look for new and better electrode materials. Anodes, for example, are currently made from carbon in the form of graphite. That carbon could be replaced by silicon, which can hold up to ten times as many lithium ions per gram of electrode. The drawback is that when the battery is charged, a silicon anode will expand to more than three times its normal size as it fills with lithium ions. This may break up the electrode, and possibly even the battery casing.

A better alternative may be to replace carbon with pure lithium metal. A lithium anode will also store up to ten times as much lithium ions per gram of electrode as graphite, but without the swelling seen in silicon anodes. Lithium anodes were, in fact, used in the early days of Li-ion batteries, but as the metal is very reactive, especially in combination with liquid electrolytes, the idea was dropped in favour of more stable alternatives. Vereecken, however, believes that progress in solid electrolytes means it is “high time to revisit lithium metal as a material for the anode”, especially since it is possible to add protective functional coatings to nanoparticles.

Disruptive innovations are on the horizon for cathodes as well. Lithium-sulphur, for example, is a promising material that could store more energy than today’s technology allows. Indeed, the “ideal” lithium battery might well feature a lithium-air (lithium peroxide) cathode in combination with a pure lithium anode. But whereas the material composition of these batteries sounds simple, the path to realizing them will not be so easy, and there is still some way to go before any of these developments will be integrated into commercial batteries. Once that happens, though, huge payoffs are possible. The most obvious would be electrical cars that drive farther and charge faster, but better lithium batteries could also be the breakthrough needed to make renewable power ubiquitous – and thus finally let us off the fossil-fuel hook.

Genesis Nanotechnology, Inc. is pleased to present Tenka Energy, Inc. Building Ultra-Thin Energy Dense SuperCaps and NexGen Nano-Enabled Pouch & Cylindrical Batteries – Energy Storage Made Small and POWERFUL! YouTube Video

 

 

Update EV News: Volvo buys a stake in electric charging firm FreeWire Technologies


Volvo and MOBI

Oct. 24, 2018

Volvo Cars has acquired a stake in electric car charging company FreeWire Technologies via the Volvo Cars Tech Fund, deepening the company’s commitment to a fully electric future. (See Industry Announcement Below)

While Volvo Cars’s electrification strategy does not envision direct ownership of charging or service stations, the investment in FreeWire reinforces its overall commitment to supporting a widespread transition to electric mobility together with other partners.

FWire mobisLeafsFreeWire is a San Francisco-based company that has been a pioneer in flexible fast-charging technology for electric cars. It specialises in both stationary and mobile fast charging technology, allowing electric car charging to be deployed quickly and widely. (Check Out FWT’s website – Featuring ‘MOBI’)  FreeWire Technologies – Electrification Beyond the Grid

Installing traditional fixed fast-charging stations is usually a cost- and labour intensive process that requires a lot of electrical upgrades to support the connection between charging stations and the main electrical grid. FreeWire’s charging stations remove that complication and use low-voltage power, allowing operators to simply use existing power outlets. This means drivers can enjoy all the benefits of fast charging without operators needing to go through the hassle of establishing a high-voltage connection to the grid.

Volvo Cars has one of the auto industry’s most ambitious electrification strategies. Every new Volvo car launched from 2019 will be electrified, and by 2025 the company aims for fully electric cars to make up 50 per cent of its overall global sales.

“Volvo Cars’ future is electric, as reflected by our industry-leading commitment to electrify our entire product range,” said Zaki Fasihuddin, CEO of the Volvo Cars Tech Fund. “To support wider consumer adoption of electric cars, society needs to make charging an electric car as simple as filling up your tank. Our investment in FreeWire is a firm endorsement of the company’s ambitions in this area.”

“FreeWire’s fast charging technology holds great promise to simplify the experience for customers of electrified Volvos,” said Atif Rafiq, chief digital officer at Volvo Cars. “With this move, we aim to make the future of sustainable, electric cars more practical and convenient.”

“We’re thrilled to partner with Volvo Cars to develop new markets and business models around our EV fast charging and ultra-fast charging technology,” said Arcady Sosinov, CEO of FreeWire. “Having a car maker with both the legacy and future vision of Volvo is going to give us access to technology, testing, and new strategies that will really accelerate the growth of the company.”

The Volvo Cars Tech Fund was launched earlier this year and aims to invest in high-potential technology start-ups around the globe. It focuses its investments on strategic technology trends transforming the auto industry, such as artificial intelligence, electrification, autonomous drive and digital mobility services.

Earlier this year, the Volvo Cars Tech Fund announced its first investment in Luminar Technologies, a leading start-up in the development of advanced sensor technology for use in autonomous vehicles, with whom Volvo Cars collaborates on the development and testing of its LiDAR sensing technology on Volvo cars.

Companies benefit from participation by the Volvo Cars Tech Fund as they may gain the ability to validate technologies, accelerate market introduction, as well as potentially access Volvo Cars’ global network and unique position in the Chinese car market.

 

 Volvo Car Group in 2017

For the 2017 financial year, Volvo Car Group recorded an operating profit of 14,061 MSEK (11,014 MSEK in 2016). Revenue over the period amounted to 210,912 MSEK (180,902 MSEK). For the full year 2017, global sales reached a record 571,577 cars, an increase of 7.0 per cent versus 2016. The results underline the comprehensive transformation of Volvo Cars’ finances and operations in recent years, positioning the company for its next growth phase.

About Volvo Car Group

Volvo has been in operation since 1927. Today, Volvo Cars is one of the most well-known and respected car brands in the world with sales of 571,577 cars in 2017 in about 100 countries. Volvo Cars has been under the ownership of the Zhejiang Geely Holding (Geely Holding) of China since 2010. It formed part of the Swedish Volvo Group until 1999, when the company was bought by Ford Motor Company of the US. In 2010, Volvo Cars was acquired by Geely Holding.

In 2017, Volvo Cars employed on average approximately 38,000 (30,400) full-time employees. Volvo Cars head office, product development, marketing and administration functions are mainly located in Gothenburg, Sweden. Volvo Cars head office for China is located in Shanghai. The company’s main car production plants are located in Gothenburg (Sweden), Ghent (Belgium), Chengdu, Daqing (China) and Charleston (USA), while engines are manufactured in Skövde (Sweden) and Zhangjiakou (China) and body components in Olofström (Sweden).

About Volvo Cars Tech Fund Volvo download

Volvo Cars Tech Fund is a new venture fund under the Volvo Cars umbrella, and is dedicated to advancing Volvo’s mission of ecology, safety, and technology across its vehicles. The fund was established in 2018, and is based out of Volvo Cars R&D Tech Center in Mountain View, California. Read more here.

 

 

Industry Announcement

Volvo is the latest business to take an interest in FreeWire.  Swedish luxury vehicles company Volvo Cars has bought a stake in FreeWire Technologies, a California-based electric car charging business. 

The acquisition has been made through the Volvo Cars Tech Fund, which was launched earlier this year. In an announcement Wednesday, Volvo described FreeWire as a “pioneer in flexible fast charging technology for electric cars.”Volvo becomes the latest major business to take an interest in FreeWire. In January 2018, BP Ventures announced it was investing $5 million in the business. 

From 2019, every new car that Volvo launches is set to be electrified. The business wants fully-electric cars to account for 50 percent of overall global sales by the year 2025.

“To support wider consumer adoption of electric cars, society needs to make charging an electric car as simple as filling up your tank,” Zaki Fasihuddin, the Volvo Cars Tech Fund CEO, said in a statement. “Our investment in FreeWire is a firm endorsement of the company’s ambitions in this area.”

In 2017, there were more than 3 million electric and plug-in hybrid cars on the planet’s roads, according to the International Energy Agency’s (IEA) Global Electric Vehicles Outlook. This represents an increase of 54 percent compared to 2016.

Almost 580,000 electric cars were sold in China last year, according to the IEA, while around 280,000 were sold in the U.S.

In terms of charging infrastructure, the IEA says that, globally, there were an estimated 3 million private chargers at homes and workplaces in 2017. The number of “publicly accessible” chargers amounted to roughly 430,000.