Advancements in battery technology shaping the future of electronic vehicles


battery_sunx250Scientists at the Canadian Light Source are on the forefront of battery technology using cheaper materials with higher energy and better recharging rates that make them ideal for electric vehicles (EVs).

The switch from conventional internal combustion engines to EVs is well underway. However, limited mileage of current EVs due to the confined energy storage capability of available battery systems is a major reason why these vehicles are not more common on the road.

A group of researchers from the CLS and Western Univ. have made significant strides in addressing the rechargeability and reaction kinetics of sodium-air batteries. They believe understanding sodium-air battery systems and the chemical composition and charging behavior will contribute to manufacturing more road-worthy batteries for EVs.

battery_sunx250

Schematic diagram of sodium-air (Na-Air) batteries based on porous carbon electrodes. Image: Canadian Light Source

“Metal-air cells use different chemistry from conventional lithium-ion batteries, making them more suited to compete with gasoline,” said Dr. Xueliang (Andy) Sun, Canada Research Chair from Western’s Dept. of Mechanical and Materials Engineering. “Development of new rechargeable battery systems with higher energy density will increase the EVs mileage and make them more practical for everyday use.

“On the other side, higher energy density battery systems will pave the road for renewable energy sources in order to decrease emissions and climate change consequences,” said Sun.

During their experiments, researchers looked at different “discharge products” from the sodium-air batteries under various physicochemical conditions. Products such as sodium peroxide and sodium superoxide are produced. Understanding these discharge products is critically important to the charging cycle of the battery cell, since various oxides exhibit different charging potentials.

The experiments were conducted using the powerful x-rays of the CLS VLS-PGM beamline.

“We took advantage of the high brightness and high-energy resolution of the photoemission endstation, using a surface sensitive technique to identify the different states of the sodium oxides,” said Dr. Xiaoyu Cui, CLS staff scientist. “We could also monitor the change in the chemical composition of the products by changing the kinetic parameters of the cell. The conclusive data from the CLS helped us confirm our hypothesis.”

According to the researchers, only a few studies have ever addressed sodium-air battery systems, with limited understanding behind the chemistry of the cell. Their work was published in Energy and Environmental Science and the authors believe the findings of the study contribute to better understanding the chemistry behind sodium-air cells which, in turn, will result in improved recharging rates and energy efficiencies.

“Although lots of research has been done to develop rechargeable, high energy metal-air battery cells during the past decade, there is still a long road ahead to achieve a practical high-energy battery system that can meet the demand for our current EVs,” said Sun. “We are working to develop novel materials for different battery systems to increase the energy density and lifecycle.

“Metal-air batteries are less expensive compared with other battery systems such as lithium-ion. Specifically, sodium-air batteries are very cost effective since the materials can easily be supplied from natural resources – sodium and oxygen being among the most abundant elements on earth.”

Source: Canadian Light Source

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Nanotechnology to provide Cleaner Diesel Engines


Applications of Nanomaterials Chart Picture1It may seem paradoxical that a rare precious metal such as platinum is used in something as simple as smoky truck exhaust systems—nonetheless, this has always been a fundamental technological principle.

When it comes to diesel engine catalysts—i.e. the element responsible for cleansing exhaust fumes particles—platinum has unfortunately proved to be the only viable option, which has resulted in material costs alone accounting for half of the price of a diesel catalyst.

Such dependency on precious metals is both costly and unsustainable, which is why InnovationsFonden invested an impressive DKK 15 million—half of the total budget—in a project to find new catalyst materials based on nanotechnology.

The collaborative project involves Aarhus University, Danish Technological Institute, Dinex A/S tasked with production—and finally DTU, where will bring more than 25 years’ experience in experimental surface physics, nanotechnology and catalysis to bear.

“I have devoted myself exclusively to catalysts and surface physics since 1987. I am therefore excited by the prospect of my research finding a specific technological application,” says Ib Chorkendorff, who usually works with catalysts and nanomaterials at basic research level.

New catalysts

In essence, Aarhus University has developed a new way to manufacture catalysts and is now assessing the further development options that are opening up.

“Our idea is to try and make better catalysts for diesel engines than those currently available, and in particular, to find a viable alternative to platinum, which is, of course, a very expensive raw material,” says Ib Chorkendorff.

“We are focusing on nanoparticles because we want to maximize the surface area, but objects don’t like surfaces—two drops of water merge into one large drop to reduce surface energy, for example. The art is to create small reactive nanoparticles and keep them apart so they don’t merge together. The greater the surface area, the less material you require,” explains Ib Chorkendorff.

Each time you optimize the platinum surface, you save material and thus achieve greater effect at less cost.

Dinex A/S, the company looking to transform the research behind the new technology into new catalysts for the global market, has found it invaluable working with someone of Chorkendorff’s calibre:

“We believe that collaboration between the business sector and the research community is a win-win situation. Such partnerships hold huge untapped potential,” says Lars Christian Larsen, R & D Director, Dinex.

With the assistance of Ib Chorkendorff and the rest of the team, he hopes to achieve a 25% platinum reduction, which will rank Dinex among global leaders in catalyst production.

The project will be launched in the autumn, and in addition to Ib Chorkendorffs 25 years of experience and insight, DTU’s contribution will include a PhD student or a postdoc.

Article from DTUavisen No. 7, September 2014.

Source: Technical University of Denmark

10 Emerging Technologies That Will Change/ Have Changed (?) Your World


CNT multiprv1_jpg71ec6d8c-a1e2-4de6-acb6-f1f1b0a66d46LargerNote to Readers: It is interesting (To Us at GNT anyway) that the BOLD predictions for technology, should always be IOHO “re-visited”. What follows is the “Top 10 List” from 2004. 10 Years … How have the technology “fortune-tellers” done?!

 

 

10 Emerging Technologies That Will Change Your World

Technology Review unveils its annual selection of hot new technologies about to affect our lives in revolutionary ways-and profiles the innovators behind them.

Full Article Link Here: http://www2.technologyreview.com/featured-story/402435/10-emerging-technologies-that-will-change-your/

Technology Review: February 2004

With new technologies constantly being invented in universities and companies across the globe, guessing which ones will transform computing, medicine, communication, and our energy infrastructure is always a challenge. Nonetheless, Technology Review’s editors are willing to bet that the 10 emerging technologies highlighted in this special package will affect our lives and work in revolutionary ways-whether next year or next decade. For each, we’ve identified a researcher whose ideas and efforts both epitomize and reinvent his or her field. The following snapshots of the innovators and their work provide a glimpse of the future these evolving technologies may provide.

10 Emerging Technologies That Will Change Your World
Universal Translation
Synthetic Biology
Nanowires
T-Rays
Distributed Storage
RNAi Interference
Power Grid Control
Microfluidic Optical Fibers
Bayesian Machine Learning
Personal Genomics

Excerpt: Nanowires:

(Page 4 of 11)

PEIDONG YANG

Nanowires

Few emerging technologies have offered as much promise as nanotechnology, touted as the means of keeping the decades-long electronics shrinkfest in full sprint and transfiguring disciplines from power production to medical diagnostics. Companies from Samsung Electronics to Wilson Sporting Goods have invested in nanotech, and nearly every major university boasts a nanotechnology initiative. Red hot, even within this R&D frenzy, are the researchers learning to make the nanoscale wires that could be key elements in many working nanodevices.

“This effort is critical for the success of the whole [enterprise of] nanoscale science and technology,” says nanowire pioneer Peidong Yang of the University of California, Berkeley. Yang has made exceptional progress in fine-tuning the properties of nanowires. Compared to other nanostructures, “nanowires will be much more versatile, because we can achieve so many different properties just by varying the composition,” says Charles Lieber, a Harvard University chemist who has also been propelling nanowire development.

Genesis Nanotech Headlines Are Out!


Organ on a chip organx250Genesis Nanotech Headlines Are Out! Read All About It!

https://paper.li/GenesisNanoTech/1354215819#!headlines

Visit Our Website: www.genesisnanotech.com

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SUBCOMMITTE EXAMINES BREAKTHROUGH NANOTECHNOLOGY OPPORTUNITIES FOR AMERICA

Chairman Terry: “Nanotech is a true science race between the nations, and we should be encouraging the transition from research breakthroughs to commercial development.”

WASHINGTON, DCThe Subcommittee on Commerce, Manufacturing, and Trade, chaired by Rep. Lee Terry (R-NE), today held a hearing on:

“Nanotechnology: Understanding How Small Solutions Drive Big Innovation.”

 

 

electron-tomography

“Great Things from Small Things!” … We Couldn’t Agree More!

 

Subcommittee Examines Breakthrough Nanotechnology Opportunities for America


Applications-of-Nanomaterials-Chart-Picture1SUBCOMMITTE EXAMINES BREAKTHROUGH NANOTECHNOLOGY OPPORTUNITIES FOR AMERICA
July 29, 2014

WASHINGTON, DCThe Subcommittee on Commerce, Manufacturing, and Trade, chaired by Rep. Lee Terry (R-NE), today held a hearing on “Nanotechnology: Understanding How Small Solutions Drive Big Innovation.” Nanotechnology is science, engineering, and technology conducted at the nanoscale, which is approximately 1 to 100 nanometers (one nanometer is a billionth of a meter). This technology brings great opportunities to advance a broad range of industries, bolster our U.S. economy, and create new manufacturing jobs. Members heard from several nanotech industry leaders about the current state of nanotechnology and the direction that it is headed.UNIVERSITY OF WATERLOO - New $5 million lab

“Just as electricity, telecommunications, and the combustion engine fundamentally altered American economics in the ‘second industrial revolution,’ nanotechnology is poised to drive the next surge of economic growth across all sectors,” said Chairman Terry.

 

 

Applications of Nanomaterials Chart Picture1

Dr. Christian Binek, Associate Professor at the University of Nebraska-Lincoln, explained the potential of nanotechnology to transform a range of industries, stating, “Virtually all of the national and global challenges can at least in part be addressed by advances in nanotechnology. Although the boundary between science and fiction is blurry, it appears reasonable to predict that the transformative power of nanotechnology can rival the industrial revolution. Nanotechnology is expected to make major contributions in fields such as; information technology, medical applications, energy, water supply with strong correlation to the energy problem, smart materials, and manufacturing. It is perhaps one of the major transformative powers of nanotechnology that many of these traditionally separated fields will merge.”

Dr. James M. Tour at the Smalley Institute for Nanoscale Science and Technology at Rice University encouraged steps to help the U.S better compete with markets abroad. “The situation has become untenable. Not only are our best and brightest international students returning to their home countries upon graduation, taking our advanced technology expertise with them, but our top professors also are moving abroad in order to keep their programs funded,” said Tour. “This is an issue for Congress to explore further, working with industry, tax experts, and universities to design an effective incentive structure that will increase industry support for research and development – especially as it relates to nanotechnology. This is a win-win for all parties.”

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Professor Milan Mrksich of Northwestern University discussed the economic opportunities of nanotechnology, and obstacles to realizing these benefits. He explained, “Nanotechnology is a broad-based field that, unlike traditional disciplines, engages the entire scientific and engineering enterprise and that promises new technologies across these fields. … Current challenges to realizing the broader economic promise of the nanotechnology industry include the development of strategies to ensure the continued investment in fundamental research, to increase the fraction of these discoveries that are translated to technology companies, to have effective regulations on nanomaterials, to efficiently process and protect intellectual property to ensure that within the global landscape, the United States remains the leader in realizing the economic benefits of the nanotechnology industry.”

James Phillips, Chairman & CEO at NanoMech, Inc., added, “It’s time for America to lead. … We must capitalize immediately on our great University system, our National Labs, and tremendous agencies like the National Science Foundation, to be sure this unique and best in class innovation ecosystem, is organized in a way that promotes nanotechnology, tech transfer and commercialization in dramatic and laser focused ways so that we capture the best ideas into patents quickly, that are easily transferred into our capitalistic economy so that our nation’s best ideas and inventions are never left stranded, but instead accelerated to market at the speed of innovation so that we build good jobs and improve the quality of life and security for our citizens faster and better than any other country on our planet.”

Chairman Terry concluded, “Nanotech is a true science race between the nations, and we should be encouraging the transition from research breakthroughs to commercial development. I believe the U.S. should excel in this area.”

– See more at: http://energycommerce.house.gov/press-release/subcommittee-examines-breakthrough-nanotechnology-opportunities-america#sthash.YnSzFU10.dpuf

Hydrogen Fueling Could be Easier to Integrate Than You Think


New report could inspire Hydrogen integration into more California gas stations.

July 25, 2014
Sunmmary

Honda's Next Generation Solar Hydrogen Station PrototypeWASHINGTON – According to a report on the Greener Ideal website, a recent research study conducted by Sandia National Laboratories (SNL) may help speed up process of installing hydrogen fuel cell stations throughout the state of California.

The SNL study, which examined 70 gas stations in California, found that 14 of them could integrate hydrogen fuel right away, while another 17 only need some property expansions before they could be ready to cater to fuel cell vehicles. Integrating hydrogen storage into gas stations is a far cheaper option than building new hydrogen fueling stations from the ground up, considering that the construction of an entirely new station can cost up to $1.5 million.

In their article, Greener Ideal explains that the SNL report found that the stations ready to immediately integrate hydrogen fueling meet the requirements of the National Fire Protection Association (NFPA) hydrogen technologies code from 2011, which includes guidelines for the storage, use, piping and generation of hydrogen and is an essential tool for making sure that hydrogen fueling stations are operated in a safe manner, due to their serious flammability issues.

 

“Greener Ideal Article”

Hydrogen Fuel Can Be Easily Integrated into More Gas Stations in California

July 24, 2014

The lack of fueling stations – along with high production costs, is clearly one of the biggest hurdles for hydrogen cars, so until these issues are resolved, vehicles powered by hydrogen won’t become commonplace. As far as costs are concerned, car makers are trying to develop more affordable fuel cells, which would definitely bring the price of hydrogen cars down, but when it comes to fueling stations, a much broader effort from both the auto industry and government is needed to put the proper infrastructure in place.

Of all states, California has done the most in terms of promotion of hydrogen powered cars and encouraging a wider adoption of these alternative fuel vehicles. California has been investing heavily in the construction and installation of fueling stations across the state, and offering various incentives to those who decide to purchase one of these vehicles. Currently, there are over 20 stations in California, and the state has announced plans to install a total of 100 stations within the next 10 years. However, the pace of installing fueling stations could be much faster and a recent research study conducted by Sandia National Laboratories may help speed things up.

 

Honda's Next Generation Solar Hydrogen Station Prototype

Sandia National Laboratories completed a study that found many existing gas stations in California could accept hydrogen and cater to fuel cell vehicles. Integrating hydrogen storage into gas stations is a far cheaper option than building new hydrogen fueling stations from the ground up, considering that the construction of an entirely new station can cost up to $1.5 million. Researchers at Sandia examined 70 gas stations in California, and found that 14 of them could integrate hydrogen fuel right away, while another 17 only need some property expansions before they could be ready for it.

According to the report released by Sandia National Laboratories, the 14 stations that could readily accept hydrogen meet the requirements of the National Fire Protection Association (NFPA) hydrogen technologies code from 2011 – which includes guidelines for the storage, generation, use, piping, and generation of hydrogen. The NFPA hydrogen technologies code is an important tool for making sure that hydrogen fueling stations are operated in a safe manner, since there are serious flammability hazards involved in handling hydrogen.

Researchers were particularly focused on the distance between the different elements of the fueling infrastructure and public streets as one of the key factors to ensuring the safe operation of fueling facilities. “Whether you are filling your car with gasoline, compressed natural gas or hydrogen fuel, the fueling facility first of all must be designed and operated with safety in mind,” said Daniel Dedrick, hydrogen program manager at Sandia.

Chris San Marchi, manager of Sandia’s hydrogen and metallurgy science group, explained that scientists need to examine the potential safety hazards if there is a hydrogen leak at an existing gas station:

“If you have a hydrogen leak at a fueling station, for example, and in the event that the hydrogen ignites, we need to understand how that flame is going to behave in order to maintain and control it within a typical fueling station.”

At the moment, there are about 120,000 gas stations in the U.S., and the study Sandia National Laboratories conducted shows that many of them could cater to hydrogen fuel cell vehicles, which would definitely help expand the hydrogen fueling station network, without having to invest hundreds of millions of dollars in an entirely new infrastructure.

For the latest information on consumer perceptions about hydrogen vehicles, read this week’s NACS Daily article, “Hydrogen Cars Are Here — What Now?”

Breakthrough Method (Discovery) for Characterizing Hot Carriers Could Hold the Key to Future Solar Cell Efficiencies


XBD200209-00526-02.PSDOne of the major road blocks to the design and development of new, more efficient solar cells may have been cleared. Researchers with the Lawrence Berkeley National Laboratory (Berkeley Lab) have developed the first ab initio method – meaning a theoretical model free of adjustable or empirical parameters – for characterizing the properties of “hot carriers” in semiconductors. Hot carriers are electrical charge carriers – electrons and holes – with significantly higher energy than charge carriers at thermal equilibrium.

“Hot carrier thermalization is a major source of efficiency loss in solar cells, but because of the sub-picosecond time scale and complex physics involved, characterization of hot carriers has long been a challenge even for the simplest materials,” says Steven Louie, a theoretical physicist and senior faculty scientist with Berkeley Lab’s Materials Sciences Division (MSD). “Our work is the first ab initio calculation of the key quantities of interest for hot carriers – lifetime, which tells us how long it takes for hot carriers to lose energy, and the mean free path, which tells us how far the hot carriers can travel before losing their energy.”

XBD200209-00526-02.PSD

A new and better way to study “hot” carriers in semiconductors, a major source of efficiency loss in solar cells, has been developed by scientists at Berkeley Lab. (Photo by Roy Kaltschmidt)

All previous theoretical methods for computing these values required empirical parameters extracted from transport or optical measurements of high quality samples, a requirement that among the notable semiconductor materials has only been achieved for silicon and gallium arsenide. The ab initio method developed by Louie and Jeff Neaton, Director of the Molecular Foundry, a U.S. Department of Energy (DOE) Nanoscience User Facility hosted at Berkeley Lab, working with Marco Bernardi, Derek Vigil-Fowler and Johannes Lischner, requires no experimental parameters other than the structure of the material.

(From left) Steve Louie, Marco Bernardi, Jeff Neaton and Johannes Lischner developed the first ab initio method for characterizing hot carriers in semiconductors. (Photo by Roy Kaltschmidt)

“This means that we can study hot carriers in a variety of surfaces, nanostructures, and materials, such as inorganic and organic crystals, without relying on existing experiments,” says Neaton. “We can even study materials that have not yet been synthesized. Since we can access structures that are ideal and defect-free with our methods, we can predict intrinsic lifetimes and mean free paths that are hard to extract from experiments due to the presence of impurities and defects in real samples. We can also use our model to directly evaluate the influence of defects and impurities.”

Neaton, like Louie, is a senior MSD faculty scientist with the University of California (UC) Berkeley. Neaton also holds an appointment with the Kavli Institute for Energy Nanosciences. They are the corresponding authors of a paper in Physical Review Letters describing this work titled “Ab Initio Study of Hot Carriers in the First Picosecond after Sunlight Absorption in Silicon.” Bernardi is the lead author of the paper, and Vigil-Fowler the primary coauthor.

Single-junction solar cells based on crystalline silicon are rapidly approaching the theoretical limit of their efficiency, which is approximately 30-percent. This means that if a silicon-based solar cell collects 1,000 Watts per square meter of energy, the most electricity it can generate is 300 Watts per square meter. Hot carriers are crucial to enhancing solar cell  efficiency, since their thermalization results in the loss of as much as a third of the absorbed solar energy in silicon, and similar values in other semiconductors. However, the properties of hot carriers in complex materials for photovoltaic and other modern optoelectronic applications are still poorly understood.

“Our study was aimed at providing useful data for hot carrier dynamics in silicon with application in solar cells,” says Bernardi. “In this study we provide calculations from first principles that describe the two key loss mechanisms, induced by electrons and phonons, respectively, with state-of-the-art accuracy and within the frameworks of density functional and many-body perturbation theories.”

When the research team applied their method to study the relaxation time and mean free path of hot carriers in silicon, they found that thermalization under solar illumination is completed within 350 femtoseconds, and is dominated by phonon emission from hot carriers, a process that becomes progressively slower as the hot carriers lose energy and relax toward the band edges. This modeling result was in excellent agreement with the results of pump-probe experiments. While the model was only tested on silicon in this study, the researchers are confident it will be equally successful with other materials.

“We believe our approach is highly valuable to experimental groups studying hot carriers in the context of solar cells and other renewable energy technologies as it can be used to compute the lifetime and mean free path of hot carriers with specific energies, momenta, and crystallographic directions with unprecedented resolution,” Bernardi says. “As we expand our study of hot carriers to a range of crystalline materials and nanostructures, we believe that our data will provide unique microscopic insight to guide new experiments on hot carriers in semiconductors.”

This research was supported by the DOE Office of Science and the National Science Foundation and made use of the Molecular Foundry, as well as computational resources of the National Energy Research Scientific Computing Center (NERSC), which is also supported by the DOE Office of Science.

Additional Information

For more about the research of Steven Louie go here

For more about the research of Jeff Neaton go here

For more about the Molecular Foundry go here

For more about NERSC go here

For more about the Kavli Institute for Energy Nanosciences go here

– See more at: http://newscenter.lbl.gov/2014/07/17/first-ab-initio-method-for-characterizing-hot-carriers/#sthash.wY178h9s.dpuf

Univeristy of Alberta Researchers Develop Next Generation Battery


UniversityOfAlberta_UglyLogo_1-796768

New technology yields potential for faster-charging, longer-lasting batteries to power future electronic devices.  By Nicole Basaraba on July 3, 2014

(Edmonton) A research team from the University of Alberta has used carbon nanomaterials to develop next-generation batteries capable of charging faster and lasting longer than today’s standard lithium-ion batteries. “What we’ve done is develop a new electrochemistry technology that can provide high energy density and high power density for the next generation,” said lead researcher Xinwei Cui, who completed his PhD in materials engineering at the U of A in 2010 and is now chief technology officer at AdvEn Solutions, a technology development company that is working on the battery so it can be commercially manufactured for use in electronic devices.

The research team developed the new technology for energy storage using a process called induced fluorination. “We tried lots of different materials. Normally carbon is used as the anode in lithium-ion batteries, but we used carbon as the cathode, and this is used to build a battery with induced fluorination,” Cui explained. The advantages of using carbon are that it is cost-effective and safe to use, and the energy output is five to eight times higher than lithium-ion batteries currently on the market.

Xinwei Cui

Xinwei Cui holds one of the nano-engineered carbon components of the new battery technology. (Photo: David Dodge)

 

The new battery also performs better than two other future technologies: lithium-sulfur batteries, currently in the prototype stage, and lithium-air batteries, now under development. For example, the induced-fluorination technology could be used to produce cellphone batteries that would charge faster and last longer. “Nobody knew that carbon could be used as a cathode with such a high performance. That is what’s unique with our technology and what is detailed in our paper,” Cui said.  morpheus-human-battery

The team published their findings in the journal Nature Scientific Reports. The paper was written by Cui; Jian Chen, a researcher in the National Institute for Nanotechnology; Tianfei Wang, a PhD candidate in materials engineering; and Weixing Chen, professor of chemical and materials engineering at the U of A.

“It wasn’t a quick process. Once we found carbon is different, we persisted for three years until we got results,” Cui said. AdvEn Solutions hopes to have a prototype by the end of 2014 and aims to develop three versions of the battery to serve different goals.

One battery would have a high power output and a long life cycle, the second would have high energy for quick charging, and the third a super-high energy storage. “We have a long way to go, but we’re on the right track. It’s exciting work and we want everyone to know about it and that it’s very young but promising,” said Cui. AdvEn is a growing company housed within the Department of Chemical and Materials Engineering at the U of A. It aims to expand by taking on new researchers and gaining more funding. The company recently secured a partnership with the U.S.-based aerospace company Lockheed Martin to develop an advanced anode for AdvEn’s high-performance carbon cathode.

 

Nanotechnology & Supercapacitors for Mainstreaming Electric Cars


electric cars imagesElectric cars are very much welcomed in Norway and they are a common sight on the roads of the Scandinavian country – so much so that electric cars topped the list of new vehicle registrations for the second time. This poses a stark contrast to the situation in Germany, where electric vehicles claim only a small portion of the market. Of the 43 million cars on the roads in Germany, only a mere 8000 are electric powered.
The main factors discouraging motorists in Germany from switching to electric vehicles are the high investments cost, their short driving ranges and the lack of charging stations. Another major obstacle en route to the mass acceptance of electric cars is the charging time involved. The minutes involved in refueling conventional cars are so many folds shorter that it makes the situation almost incomparable.
However, the charging durations could be dramatically shortened with the inclusion of supercapacitors. These alternative energy storage devices are fast charging and can therefore better support the use of economical energy in electric cars. Taking traditional gasoline-powered vehicles for instance, the action of braking converts the kinetic energy into heat which is dissipated and unused. Per contra, generators on electric vehicles are able to tap into the kinetic energy by converting it into electricity for further usage. This electricity often comes in jolts and requires storage devices that can withstand high amount of energy input within a short period of time. In this example, supercapacitors with their capability in capturing and storing this converted energy in an instant fits in the picture wholly.
Unlike batteries that offer limited charging/discharging rates, supercapacitors require only seconds to charge and can feed the electric power back into the air-conditioning systems, defogger, radio, etc. as required.
Rapid energy storage devices are distinguished by their energy and power density characteristics – in other words, the amount of electrical energy the device can deliver with respect to its mass and within a given period of time.
A graphene-based supercapacitor
A graphene-based supercapacitor.
Supercapacitors are known to possess high power density, whereby large amounts of electrical energy can be provided or captured within short durations, albeit at a short-coming of low energy density. The amount of energy in which supercapacitors are able to store is generally about 10% that of electrochemical batteries (when the two devices of same weight are being compared).
This is precisely where the challenge lies and what the ElectroGraph project is attempting to address. ElectroGraph is a project supported by the EU and its consortium consists of ten partners from both research institutes and industries. One of the main tasks of this project is to develop new types of supercapacitors with significantly improved energy storage capacities.
As the project is approaches its closing phase in June, the project coordinator at Fraunhofer Institute for Manufacturing Engineering and Automation IPA in Stuttgart, Carsten Glanz explained the concept and approach taken en route to its successful conclusion: “during the storage process, the electrical energy is stored as charged particles attached on the electrode material.” “So to store more energy efficiently, we designed light weight electrodes with larger, usable surfaces.”
Graphene electrodes significantly improve energy efficiency
In numerous tests, the researcher and his team investigated the nano-material graphene, whose extremely high specific surface area of up to 2,600 m2/g and high electrical conductivity practically cries out for use as an electrode material. It consists of an ultrathin monolayer lattice made of carbon atoms. When used as an electrode material, it greatly increases the surface area with the same amount of material. From this aspect, graphene is showing its potential in replacing activated carbon – the material that has been used in commercial supercapacitors to date – which has a specific surface area between 1000 and 1800 m2/g.
“The space between the electrodes is filled with a liquid electrolyte,” revealed Glanz. “We use ionic liquids for this purpose. Graphene-based electrodes together with ionic liquid electrolytes present an ideal material combination where we can operate at higher voltages.”
By arranging the graphene layers in a manner that there is a gap between the individual layers, the researchers were able to establish a manufacturing method that efficiently uses the intrinsic surface area available of this nano-material. This prevents the individual graphene layers from restacking into graphite, which would reduce the storage surface and consequently the amount of energy storage capacity.
“Our electrodes have already surpassed commercially available one by 75 percent in terms of storage capacity,” emphasizes the engineer. “I imagine that the cars of the future will have a battery connected to many capacitors spread throughout the vehicle, which will take over energy supply during high-power demand phases during acceleration for example and ramming up of the air-conditioning system. These capacitors will ease the burden on the battery and cover voltage peaks when starting the car. As a result, the size of massive batteries can be reduced.”
In order to present the new technology, the ElectroGraph consortium developed a demonstrator consisting of supercapacitors installed in an automobile side-view mirror and charged by a solar cell in an energetically self-sufficient system. The demonstrator will be unveiled at the end of May during the dissemination workshop at Fraunhofer IPA.”
Source: Fraunhofer Gesellschaft