Despite being a promising electrode material, bulk cobalt oxide (Co3O4) exhibits poor lithium ion storage properties. Nanostructuring, e.g. making Co3O4 into ultrathin nanosheets, shows improved performance, however, Co3O4-based nanomaterials still lack long-term stability and high rate capability due to sluggish ion transport and structure degradation. Read More …
MIT: Device makes power conversion more efficient New design could dramatically cut energy waste in electric vehicles, data centers, and the power grid
Power electronics, which do things like modify voltages or convert between direct and alternating current, are everywhere. They’re in the power bricks we use to charge our portable devices; they’re in the battery packs of electric cars; and they’re in the power grid itself, where they mediate between high-voltage transmission lines and the lower voltages of household electrical sockets. Read More …
Elon Musk and Tesla have made some bold claims for the new Tesla Semi and Roadster. Those who understand batteries have been scratching their heads trying to figure out how the company can deliver the specs it’s promising – and concluding that the only possible way is some as-yet-unannounced advancement in battery technology. Read More …
Watch Our Video on New Energy Storage Technology: Supercapacitors and Batteries
20 Jul 2017
Genesis Nanotechnology, Inc.
“Great Things from Small Things” ~ GNT™
Read this edition of Genesis Nanotechnology Online featuring:
14 Jul 2017
Original Report from IDTechEX
Volvo Cars has been in the news recently in relation to their announcement this Wednesday on their decision to leave the internal combustion engine only based automotive industry. The Chinese-European company announced that from 2019 all their vehicles will be either pure electric or hybrid electric. In this way it has been argued the company is making a bold move towards electrification of vehicles. Volvo to capture potential market in China The company will launch a pure electric car in 2019 and that is a great move indeed, considering that the company has been owned by Chinese vehicle manufacturer Geely since 2010.
The Chinese electric vehicle market has been booming in the last years reaching a sales level of 350,000 plug-in EVs (pure electric and plug-in hybrid electric cars) in 2016. The Chinese plug-in EV market grew 300% from 2014 to 2015 but cooled down to 69% growth in 2016 vs 2015, still pushing a triple digit growth in pure electric cars. The Chinese government has announced that in 2017 sales will reach 800,000 NEV (new energy vehicles including passenger and bus, both pure electric and hybrid electric). IDTechEx believes that China will not make it to that level, but will definitely push the figures close to that mark.
We think that the global plug-in electric vehicle market will surpass 1 million sales per year for the first time at the end of 2017. Until recently this market has been mostly dominated by Chinese manufacturers, being BYD the best seller of electric cars in the country with 100,000 plug-in EVs sold in 2016. Tesla polemically could not penetrate the market but in 2016 sold around 11,000 units.
Whilst the owner of Volvo Cars, Geely, is active in China selling around 17,000 pure electric cars per year, it might be that Volvo has now realized that they can leverage on their brand in the Chinese premium market to catch the huge growth opportunity in China and need to participate as soon as possible. More information on market forecasts can be found in IDTechEx Research’s report Electric Vehicles 2017-2037: Forecasts, Analysis and Opportunities.
Is Volvo Cars’ move a revolutionary one? Not really, as technically speaking the company is not entirely making a bold movement to only 100% “strong” hybrid electric and pure electric vehicles. This is because the company will launch in 2019 a “mild” hybrid electric vehicles,this is also known in the industry as 48V hybrid electric platform. This is a stepping stone between traditional internal combustion engine companies and “strong” hybrid electric vehicles such as the Toyota Prius.
The 48V platform is being adopted by many automotive manufacturers, not only Volvo. OEMs like Continental developed this platform to provide a “bridge technology” towards full EVs for automotive manufacturers, providing 6 to 20 kW electric assistance. By comparison, a full hybrid system typically offers 20-40-kW and a plug-in hybrid, 50-90 kW. Volvo had already launched the first diesel plug-in hybrid in 2012 and the company will launch a new plug-in hybrid platform in 2018 in addition to the launch of the 2019 pure electric vehicle platform. Going only pure electric and plug-in hybrid electric would be really revolutionary. See IDTechEx Research’s report Mild Hybrid 48V Vehicles 2017-2027 for more information on 48V platforms.
Additional Information: The Tesla Model ‘S’
The Tesla Model S is a full-sized all-electric five-door, luxury liftback, produced by Tesla, Inc., and introduced on 22 June 2012. It scored a perfect 5.0 NHTSA automobile safety rating. The EPA official rangefor the 2017 Model S 100D, which is equipped with a 100 kWh(360 MJ) battery pack, is 335 miles (539 km), higher than any other electric car. The EPA rated the 2017 90D Model S’s energy consumption at 200.9 watt-hours per kilometer (32.33 kWh/100 mi or 20.09 kWh/100 km) for a combined fuel economy of 104 miles per gallon gasoline equivalent (2.26 L/100 km or 125 mpg‑imp). In 2016, Tesla updated the design of the Model S to closely match that of the Model X. As of July 2017, the following versions are available: 75, 75D, 90D, 100D and P100D.
For more specific details on the updated Tesla Battery Pack go here:
A radical move would be to drop diesel engines On-road diesel vehiclesproduce approximately 20% of global anthropogenic emissions of nitrogen oxides (NOx), which are key PM and ozone precursors. Diesel emission pollutions has been confirmed as a major source of premature mortality. A recent study published in Nature by the Environmental Health Analytics LLC and the International Council on Clean Transportation both based in Washington, USA found that whilst regulated NOx emission limits in leading markets have been progressively tightened, current diesel vehicles emit far more NOx under real-world operating conditions than during laboratory certification testing. The authors show that across 11 markets, representing approximately 80% of global diesel vehicle sales, nearly one-third of on-road heavy-duty diesel vehicle emissions and over half of on-road light-duty diesel vehicle emissions are in excess of certification limits. These emissions were associated with about 38,000 premature deaths globally in 2015.
The authors conclude that more stringent standards are required in order to avoid 174,000 premature deaths globally in 2040. Diesel cars account for over 50 percent of all new registrations in Europe, making the region by far the world’s biggest diesel market. Volvo Cars, sells 90 percent of its XC 90 off roaders in Europe with diesel engines. “From today’s perspective, we will not develop any more new generation diesel engines,” said Volvo’s CEO Hakan Samuelsson told German’s Frankfurter Allgemeine Zeitung in an interview . Samuelsson declared that Volvo Cars aims to sell 1 million “electrified” cars by 2025, nevertheless he refused to be drawn on when Volvo Cars will sell its last diesel powered vehicle.
Goldman Sachs believes a regulatory crackdown could add 300 euros ($325) per engine to diesel costs that are already some 1,300 euros above their petrol-powered equivalents, as carmakers race to bring real NOx emissions closer to their much lower test-bench scores. Scandinavia’s vision of a CO2-free economy Volvo’s decision should also be placed in a wider context regarding the transition to an environmentally sustainable economy.
Scandinavia’s paper industry has made great strides towards marketing itself as green and eco-aware in the last decades, so much so that countries like Norway have tripled the amount of standing wood in forests compared to 100 years ago. Energy supply is also an overarching theme, with each one of the four Scandinavian countries producing more than 39% of their electricity with renewables (Finland 39%, Sweden and Denmark 56%, Norway 98%). Finally, strong public incentives have made it possible for electric vehicles to become a mainstream market in Norway, where in 2016, one in four cars sold was a plug-in electric, either pure or hybrid. It is then of no surprise that the first battery Gigafactory announcement in Europe came from a Swedish company called Northvolt (previously SGF Energy).
The Li-ion factory will open in 4 steps, with each one adding 8 GWh of production capacity. This gives a projected final output of 32 GWh, but if higher energy cathodes are developed, 40-50 GWh capacity can be envisioned. A site has not yet been identified, but the choice has been narrowed down to 6-7 locations, all of them in the Scandinavian region. The main reasons to establish a Gigafactory there boil down to the low electricity prices (hydroelectric energy), presence of relevant mining sites, and the presence of local know-how from the pulp & paper industry. After a long search for a European champion in the EV market, it finally seems that Sweden has accepted to take the lead, and compete with giants like BYD and rising stars like Tesla. This could be the wake-up call for many other European car makers, which have been rather bearish towards EV acceptance despite many bold announcements. To learn more about IDTechEx’s view on electric vehicles, and our projections up to 2037, please check our master report on the subject http://www.IDTechEx.com/ev .
Top image source: Volvo Cars Learn more at the next leading event on the topic: Business and Technology Insight Forum. Korea 2017 on 19 – 21 Sep 2017 in Seoul, Korea hosted by IDTechEx.
More Information on ‘NextGen Magnum SuperCap-Battery Pack’ that could propel a Tesla Model ‘S’ 90% farther (almost double) and cost 1/2 (one-half) as much: Video
11 Jul 2017
Through nanotechnology, physicists Dr Raymond McQuaid, Dr Amit Kumar and Professor Marty Gregg from Queen’s University’s School of Mathematics and Physics, have created unique 2-D sheets, called domain walls, which exist within crystalline materials.
The sheets are almost as thin as the wonder-material graphene, at just a few atomic layers. However, they can do something that graphene can’t – they can appear, disappear or move around within the crystal, without permanently altering the crystal itself.
This means that in future, even smaller electronic devices could be created, as electronic circuits could constantly reconfigure themselves to perform a number of tasks, rather than just having a sole function.
Professor Marty Gregg explains: “Almost all aspects of modern life such as communication, healthcare, finance and entertainment rely on microelectronic devices.
The demand for more powerful, smaller technology keeps growing, meaning that the tiniest devices are now composed of just a few atoms – a tiny fraction of the width of human hair.”
“As things currently stand, it will become impossible to make these devices any smaller – we will simply run out of space. This is a huge problem for the computing industry and new, radical, disruptive technologies are needed. One solution is to make electronic circuits more ‘flexible’ so that they can exist at one moment for one purpose, but can be completely reconfigured the next moment for another purpose.”
The team’s findings, which have been published in Nature Communications, pave the way for a completely new way of data processing.
Professor Gregg says: “Our research suggests the possibility to “etch-a-sketch” nanoscale electrical connections, where patterns of electrically conducting wires can be drawn and then wiped away again as often as required.
“In this way, complete electronic circuits could be created and then dynamically reconfigured when needed to carry out a different role, overturning the paradigm that electronic circuits need be fixed components of hardware, typically designed with a dedicated purpose in mind.”
There are two key hurdles to overcome when creating these 2-D sheets, long straight walls need to be created. These need to effectively conduct electricity and mimic the behavior of real metallic wires. It is also essential to be able to choose exactly where and when the domain walls appear and to reposition or delete them.
Through the research, the Queen’s researchers have discovered some solutions to the hurdles. Their research proves that long conducting sheets can be created by squeezing the crystal at precisely the location they are required, using a targeted acupuncture-like approach with a sharp needle. The sheets can then be moved around within the crystal using applied electric fields to position them.
Dr Raymond McQuaid, a recently appointed lecturer in the School of Mathematics and Physics at Queen’s University, added: “Our team has demonstrated for the first time that copper-chlorine boracite crystals can have straight conducting walls that are hundreds of microns in length and yet only nanometres thick.
The key is that, when a needle is pressed into the crystal surface, a jigsaw puzzle-like pattern of structural variants, called “domains”, develops around the contact point. The different pieces of the pattern fit together in a unique way with the result that the conducting walls are found along certain boundaries where they meet.
“We have also shown that these walls can then be moved using applied electric fields, therefore suggesting compatibility with more conventional voltage operated devices. Taken together, these two results are a promising sign for the potential use of conducting walls in reconfigurable nano-electronics.”
More information: Raymond G.P. McQuaid et al. Injection and controlled motion of conducting domain walls in improper ferroelectric Cu-Cl boracite, Nature Communications (2017). DOI: 10.1038/ncomms15105
Provided by: Queen’s University Belfast
11 Jul 2017
New research shows graphene can filter common salts from water to make it safe to drink Findings could lead to affordable desalination technology
Graphene-oxide membranes have attracted considerable attention as promising candidates for new filtration technologies. Now the much sought-after development of making membranes capable of sieving common salts has been achieved.
New research demonstrates the real-world potential of providing clean drinking water for millions of people who struggle to access adequate clean water sources.
The new findings from a group of scientists at The University of Manchester were published today in the journal Nature Nanotechnology.
Previously graphene-oxide membranes have shown exciting potential for gas separation and water filtration.
Graphene-oxide membranes developed at the National Graphene Institute have already demonstrated the potential of filtering out small nanoparticles, organic molecules, and even large salts. Until now, however, they couldn’t be used for sieving common salts used in desalination technologies, which require even smaller sieves.
Previous research at The University of Manchester found that if immersed in water, graphene-oxide membranes become slightly swollen and smaller salts flow through the membrane along with water, but larger ions or molecules are blocked.
The Manchester-based group have now further developed these graphene membranes and found a strategy to avoid the swelling of the membrane when exposed to water.
The pore size in the membrane can be precisely controlled which can sieve common salts out of salty water and make it safe to drink.
Realisation of scalable membranes with uniform pore size down to atomic scale is a significant step forward and will open new possibilities for improving the efficiency of desalination technology.
Professor Rahul Raveendran Nair
As the effects of climate change continue to reduce modern city’s water supplies, wealthy modern countries are also investing in desalination technologies. Following the severe floods in California major wealthy cities are also looking increasingly to alternative water solutions.
When the common salts are dissolved in water, they always form a ‘shell’ of water molecules around the salts molecules. This allows the tiny capillaries of the graphene-oxide membranes to block the salt from flowing along with the water. Water molecules are able to pass through the membrane barrier and flow anomalously fast which is ideal for application of these membranes for desalination.
Professor Rahul Nair, at The University of Manchester said: “Realisation of scalable membranes with uniform pore size down to atomic scale is a significant step forward and will open new possibilities for improving the efficiency of desalination technology.
“This is the first clear-cut experiment in this regime. We also demonstrate that there are realistic possibilities to scale up the described approach and mass produce graphene-based membranes with required sieve sizes.”
Mr. Jijo Abraham and Dr. Vasu Siddeswara Kalangi were the joint-lead authors on the research paper: “The developed membranes are not only useful for desalination, but the atomic scale tunability of the pore size also opens new opportunity to fabricate membranes with on-demand filtration capable of filtering out ions according to their sizes.” said Mr. Abraham.
By 2025 the UN expects that 14% of the world’s population will encounter water scarcity. This technology has the potential to revolutionise water filtration across the world, in particular in countries which cannot afford large scale desalination plants.
It is hoped that graphene-oxide membrane systems can be built on smaller scales making this technology accessible to countries which do not have the financial infrastructure to fund large plants without compromising the yield of fresh water produced.
A UK-based team of researchers has created a graphene-based sieve capable of removing salt from seawater.
The sought-after development could aid the millions of people without ready access to clean drinking water. The promising graphene oxide sieve could be highly efficient at filtering salts, and will now be tested against existing desalination membranes.
It has previously been difficult to manufacture graphene-based barriers on an industrial scale. Reporting their results in the journal Nature Nanotechnology, scientists from the University of Manchester, led by Dr Rahul Nair, shows how they solved some of the challenges by using a chemical derivative called graphene oxide.
Advanced materials is one of The University of Manchester’s research beacons – examples of pioneering discoveries, interdisciplinary collaboration and cross-sector partnerships that are tackling some of the biggest questions facing the planet. #ResearchBeacons
17 Jun 2017
Tesla is revolutionizing batteries for electric bicycles and it has to do with the recent changes at the leading battery cell makers BMZ, Panasonic, Sony, Samsung and LG. Together these five make out some 80% of the world production of battery cells.
These five cell makers used to supply huge numbers of cylindrical shaped cells to the IT industry until the industry changed completely from using cylindrical shaped cells to flat shaped batteries which are now used in laptops, tablets and smartphones. Tesla placing huge orders for cylindrical shaped cells pushed battery cell makers to new highs.
Europe’s largest battery maker BMZ boss introduced the 21700 cell that will revolutionize electric bicycles. In particular as the 21700 cell not only offers a much prolonged lifetime but also batteries with a much bigger capacity for more power and pedal-supported mileage.
The extraordinary features that the 21700 battery cell brings to e-bikes will be the new standard in e-bike batteries. And that this new standard will already be available in 2018.
Instead of the current 18650 (18mm diameter and 65mm high) cell size the 21700 cell is 21mm diameter and 70mm high. The bigger size is bringing a bigger output; up to 4.8Ah. With that capacity the battery lifetime is extended from the current some 500 charging cycles up to 1,500 to 2,000 cycles.
BMZ, together with another global battery player, managed to develop batteries that offer a much longer lifespan thanks to the fact that the new batteries create less heat and has up to 60% more capacity.
Researchers have developed a solar paint that can absorb water vapour and split it to generate hydrogen – the cleanest source of energy.
The paint contains a newly developed compound that acts like silica gel, which is used in sachets to absorb moisture and keep food, medicines and electronics fresh and dry.
But unlike silica gel, the new material, synthetic molybdenum-sulphide, also acts as a semi-conductor and catalyses the splitting of water atoms into hydrogen and oxygen.
Lead researcher Dr Torben Daeneke, from RMIT University in Melbourne, Australia, said: “We found that mixing the compound with titanium oxide particles leads to a sunlight-absorbing paint that produces hydrogen fuel from solar energy and moist air.
“Titanium oxide is the white pigment that is already commonly used in wall paint, meaning that the simple addition of the new material can convert a brick wall into energy harvesting and fuel production real estate.
“Our new development has a big range of advantages,” he said. “There’s no need for clean or filtered water to feed the system. Any place that has water vapour in the air, even remote areas far from water, can produce fuel.”
His colleague, Distinguished Professor Kourosh Kalantar-zadeh, said hydrogen was the cleanest source of energy and could be used in fuel cells as well as conventional combustion engines as an alternative to fossil fuels.
“This system can also be used in very dry but hot climates near oceans. The sea water is evaporated by the hot sunlight and the vapour can then be absorbed to produce fuel.
“This is an extraordinary concept – making fuel from the sun and water vapour in the air.”
More information: Torben Daeneke et al, Surface Water Dependent Properties of Sulfur-Rich Molybdenum Sulfides:
Electrolyteless Gas Phase Water Splitting, ACS Nano (2017). DOI: 10.1021/acsnano.7b01632
Provided by: RMIT University
17 Jun 2017
Could a new material involving a carbon nanotube and graphene hybrid put an end to the dendrite problem in lithium batteries?
The high energy capacity of lithium-ion batteries has led to them powering everything from tiny mobile devices to huge trucks. But current lithium-ion battery technology is nearing its limits and the search is on for a better lithium battery. But one thing stands in the way: dendrites. If a new technology by Rice University scientists lives up to its potential, it could solve this problem and enable lithium-metal batteries that can hold three times the energy of lithium-ion ones.
Dendrites are microscopic lithium fibers that form on the anodes during the charging process, spreading like a rash till they reach the other electrode and causing the battery to short circuit. As companies such as Samsung know only too well, this can cause the battery to catch fire or even explode.
“Lithium-ion batteries have changed the world, no doubt,” says chemist Dr. James Tour, who led the study. “But they’re about as good as they’re going to get. Your cellphone’s battery won’t last any longer until new technology comes along.”
So until scientists can figure out a way to solve the problem of dendrites, we’ll have to put our hopes for a higher capacity, faster-charging battery that can quell range anxiety on hold. This explains why there’s been no shortage of attempts to solve this problem, from using Kevlar to slow down dendrite growth to creating a new electrolyte that could lead to the development of an anode-free cell. So how does this new technology from Rice University compare?
For a start, it’s able to stop dendrite growth in its tracks. Key to it is a unique anode made from a material that was first created at the university five years ago. By using a covalent bond structure, it combines a two-dimensional graphene sheet and carbon nanotubes to form a seamless three-dimensional structure. As Tour explained back when the material was first unveiled:
“By growing graphene on metal (in this case copper) and then growing nanotubes from the graphene, the electrical contact between the nanotubes and the metal electrode is ohmic. That means electrons see no difference, because it’s all one seamless material.”
Close-up of the lithium metal coating the graphene-nanotube anode (Credit: Tour Group/Rice University)
Envisioned for use in energy storage and electronics applications such as supercapacitors, it wasn’t until 2014, when co-lead author Abdul-Rahman Raji was experimenting with lithium metal and the graphene-nanotube hybrid, that the researchers discovered its potential as a dendrite inhibitor.
“I reasoned that lithium metal must have plated on the electrode while analyzing results of experiments carried out to store lithium ions in the anode material combined with a lithium cobalt oxide cathode in a full cell,” says Raji. “We were excited because the voltage profile of the full cell was very flat. At that moment, we knew we had found something special.”
Closer analysis revealed no dendrites had grown when the lithium metal was deposited into a standalone hybrid anode – but would it work in a proper battery?
To test the anode, the researchers built full battery prototypes with sulfur-based cathodes that retained 80 percent capacity after more than 500 charge-discharge cycles (i.e. the rough equivalent of what a cellphone goes through in a two-year period). No signs of dendrites were observed on the anodes.
How it works
The low density and high surface area of the nanotube forest allow the lithium metal to coat the carbon hybrid material evenly when the battery is charged. And since there is plenty of space for the particles to slip in and out during the charge and discharge cycle, they end up being evenly distributed and this stops the growth of dendrites altogether.
According to the study, the anode material is capable of a lithium storage capacity of 3,351 milliamp hours per gram, which is close to pure lithium’s theoretical maximum of 3,860 milliamp hours per gram, and 10 times that of lithium-ion batteries. And since the nanotube carpet has a low density, this means it’s able to coat all the way down to substrate and maximize use of the available volume.
“Many people doing battery research only make the anode, because to do the whole package is much harder,” says Tour. “We had to develop a commensurate cathode technology based upon sulfur to accommodate these ultrahigh-capacity lithium anodes in first-generation systems. We’re producing these full batteries, cathode plus anode, on a pilot scale, and they’re being tested.”
The study was published in ACS Nano.
Source: Rice University
17 Jun 2017
Electrodes are critical parts of every battery architecture — charge too fast, and you can decrease the charge-discharge cycle life or damage the battery so it won’t charge anymore. Scientists have built a new design and chemistry for electrodes. Their design involves advanced, nanostructured electrodes containing molybdenum disulfide and carbon nanofibers (Advanced Energy Materials, “Pseudocapacitive charge storage in thick composite MoS2 nanocrystal-based electrodes”). These composite materials have internal atomic-scale pathways. These paths are for both fast ion and electron transport, allowing for fast charging.
|Battery electrodes made of a molybdenum disulfide nanocrystal composite have internal pathways to allow lithium ions to move quickly through the electrode, speeding up the rate that the battery can charge. The key features in the structure that enable the flow of the lithium ions are the small, 20-40 nanometer, diameter of the nanocrystals (in contrast, human hairs are about 100,000 nanometers in diameter) coupled with the porosity and planar lamellar pathways shown in the electron micrograph. (Image: Sarah Tolbert, University of California, Los Angeles)|
|The new battery electrodes provide several benefits. The electrodes allow fast charging. They also have stable charge/discharge behavior, so the batteries last longer. These electrodes show promise for practical electrical energy storage systems.|
|New battery electrodes based on nanostructured molybdenum disulfide combine the ability to charge in seconds with high capacity and long cycle life. Typical lithium-ion batteries charge slowly due to slow diffusion of lithium ions within the solid electrode.|
|Another type of energy storage device (a.k.a., pseudocapacitors), which has similarities to the capacitors found in common electrical circuits, speeds up the charging process by using reactions at or near the electrode surface, thus avoiding slow solid-state diffusion pathways.|
|Nanostructured electrodes allow the creation of large surface areas so that the battery can work more like a pseudocapacitor. In this work at the University of California, Los Angeles, scientists made nanostructured electrodes from a molybdenum disulfide-carbon composite.|
|Many electrodes are based on metal oxides, but because sulfur more weakly interacts with lithium than oxygen, lithium atoms can move more freely in the metal sulfide than the metal oxide. The result is a battery electrode that shows high capacity and very fast charging times.|
|The novel electrodes deliver specific capacities of 90 mAh/g (about half that of a typical lithium-ion battery cathode) charging in less than 20 seconds, and retain over 80 percent of their original capacity after 3,000 charge/discharge cycles. Capacities of greater than 180 mAh/g (similar to cathodes in conventional lithium-ion cells) are achieved at slower charging rates.|
|The results have exciting implications for the development of fast-charging energy storage systems that could replace traditional lithium-ion batteries.|
|Source: U.S. Department of Energy, Office of Science|
15 May 2017
Researchers from UCLA and the University of Connecticut have designed a new biofriendly energy storage system called a biological supercapacitor, which operates using charged particles, or ions, from fluids in the human body. The device is harmless to the body’s biological systems, and it could lead to longer-lasting cardiac pacemakers and other implantable medical devices. The UCLA team was led by Richard Kaner, a distinguished professor of chemistry and biochemistry, and of materials science and engineering, and the Connecticut researchers were led by James Rusling, a professor of chemistry and cell biology.
A paper about their design was published this week in the journal Advanced Energy Materials. Pacemakers — which help regulate abnormal heart rhythms — and other implantable devices have saved countless lives. But they’re powered by traditional batteries that eventually run out of power and must be replaced, meaning another painful surgery and the accompanying risk of infection. In addition, batteries contain toxic materials that could endanger the patient if they leak.
The researchers propose storing energy in those devices without a battery. The supercapacitor they invented charges using electrolytes from biological fluids like blood serum and urine, and it would work with another device called an energy harvester, which converts heat and motion from the human body into electricity — in much the same way that self-winding watches are powered by the wearer’s body movements. That electricity is then captured by the supercapacitor. “Combining energy harvesters with supercapacitors can provide endless power for lifelong implantable devices that may never need to be replaced,” said Maher El-Kady, a UCLA postdoctoral researcher and a co-author of the study.
Modern pacemakers are typically about 6 to 8 millimeters thick, and about the same diameter as a 50-cent coin; about half of that space is usually occupied by the battery. The new supercapacitor is only 1 micrometer thick — much smaller than the thickness of a human hair — meaning that it could improve implantable devices’ energy efficiency. It also can maintain its performance for a long time, bend and twist inside the body without any mechanical damage, and store more charge than the energy lithium film batteries of comparable size that are currently used in pacemakers. “Unlike batteries that use chemical reactions that involve toxic chemicals and electrolytes to store energy, this new class of biosupercapacitors stores energy by utilizing readily available ions, or charged molecules, from the blood serum,” said Islam Mosa, a Connecticut graduate student and first author of the study.
The new biosupercapacitor comprises a carbon nanomaterial called graphene layered with modified human proteins as an electrode, a conductor through which electricity from the energy harvester can enter or leave. The new platform could eventually also be used to develop next-generation implantable devices to speed up bone growth, promote healing or stimulate the brain, Kaner said.
Although supercapacitors have not yet been widely used in medical devices, the study shows that they may be viable for that purpose. “In order to be effective, battery-free pacemakers must have supercapacitors that can capture, store and transport energy, and commercial supercapacitors are too slow to make it work,” El-Kady said. “Our research focused on custom-designing our supercapacitor to capture energy effectively, and finding a way to make it compatible with the human body.” Among the paper’s other authors are the University of Connecticut’s Challa Kumar, Ashis Basu and Karteek Kadimisetty. The research was supported by the National Institute of Health’s National Institute of Biomedical Imaging and Bioengineering, the NIH’s National Institute of Environmental Health Sciences, and a National Science Foundation EAGER grant. Source and top image: UCLA Engineering