Superionic Batteries – Are We There Yet?

Tohoku University, near the northern Japanese city of Sendai, finds, in a recent paper, “…The development of complex hydride solid electrolytes that exhibit high ionic conductivity at room temperature will be a revolutionary breakthrough for all-solid-state batteries employing a lithium metal anode.”  Researchers at the University lists the potential energy density for a battery using these so-called “superionic” materials as greater than 2,500 Watt-hours per kilogram “at a high current density of 5,016 miliAmps per gram.   This energy density would result in the fabled 10X battery – ten times the energy density of a conventional lithium-ion battery – that has been the subject of international research for the last decade.

Tohoku’s press release states, “Scientists from Tohoku University and the High Energy Accelerator Research Organization have developed a new complex hydride lithium superionic conductor that could result in all-solid-state batteries with the highest energy density to date:”  Led by Sangryun Kim from the Institute of Material Research (IMR) and Shin-ichi Orimo from the Advanced Institute for Materials Research (AIMR), the study looked for such conductors based on complex hydrides (anions of hydrogen).  this is a difficult search, because the potential high energy density of these materials is balanced by the normal instability of the hydrides.

High-energy-density all-solid-state lithium metal batteries. a Schematic illustration of the prepared all-solid-state batteries. S, Li/0.7Li(CB9H10)–0.3Li(CB11H12), and lithium metal were used as the cathodes, solid electrolytes, and anodes, respectively. b Voltage profiles for a rate of 0.03 C (50.2 mA g−1) at 25 °C during the first two cycles. c Discharge–charge profiles at 0.03, 0.05, 0.1, 0.3, and 1 C after an initial cycle at 25 °C. d Capacity retention as a function of current density. e, f Cycling performances of discharge capacity and coulombic efficiency (e) for a rate of 1 C at 25 °C and (f) for a discharging rate of 3 C and a charging rate of 1 C at 50 °C

The researchers’ paper, “A complex hydride lithium superionic conductor for high-energy-density all-solid-state lithium metal batteries,” was published in Nature Communications on March 6, 2019.  The authors, Sangryun KimHiroyuki OguchiNaoki ToyamaToyoto SatoShigeyuki TakagiToshiya OtomoDorai ArunkumarNaoaki KuwataJunichi Kawamura and Shin-ichi Orimo, were able to overcome the high ion transfer resistance found in using solid electrolytes with lithium metal anodes.

The paper is filled with “howevers,” noting the many instances of positive outcomes countered by negative areas of resistance.   The high energy density possible with superionic conductors was offset by the instability of the solid electrolyte against lithium metal.  As the solid electrolyte reaches what we call “room temperatures” it tends to lose contact with the anode and reduce reactivity because the electrolyte is filled with vacancy-rich disordered cation sublattices .   Researchers managed to tame this with a finer granularity in the material that enables full contact.

The abstract ends on a promising note: “’We expect that this development will not only inspire future efforts to find lithium superionic conductors based on complex hydrides, but also open up a new trend in the field of solid electrolyte materials that may lead to the development of high-energy-density electrochemical devices,’  said Sangryun Kim of Shin-ichi Orimo’s research group at Tohoku University

Think of a 200-pound battery slimming down to 20 pounds for the same output. Range and  endurance would be Tesla-like for electric and hybrid aircraft, and following the old rule to two pounds of structure for every pound of power plant for fossil-fuel aircraft, could lead to more efficient airframes.

At the laboratory stage now, this would seem to be investment bait for venturesome venture capitalists.


A Solar Airport Profits from Vegetables

We’ve covered several airports that have found ways to make themselves environmentally friendly, including recycling the vast amounts of waste left by passengers, and installing solar panels to help run the site.

Recently honored by the United Nations. ”Cochin International Airport Limited (CIAL) has been selected for the Champion of Earth Prize -2018, the highest environmental honor instituted by United Nations. CIAL is honored for its successful execution of one of the revolutionary ideas of using solar energy which made Cochin  Airport a first in the world fully powered by it.”

Besides generating 40 megawatts of electricity from its solar panels at 2018 levels, the airport grows organic vegetables beneath those panels.  To ensure optimum land use, “CIAL has successfully implemented organic farming of vegetables in area[s] between solar panels. The airport stands at fourth in the country in terms of international traffic and seventh in total traffic has handled ten million passengers in 2017-18.”

V.J.Kurian, Managing Director for CIAL, has an integrated concept that provides power for airport services and even feeds the 8,000 employees in diverse occupations who serve the traveling public and  grow the organic produce.  Kurian explains the overall program results in annual cost savings of Rs. 40 Crore to the airport.  As explained in,  a crore is not an amount of money, but an Indian counting method, like counting things in scores or dozens.  1 Crore refers to 10,000,000, so 40 Crore = 400,000,000 million Indian Rupee (INR), or about $5,783,689.60 as of March 24 2019.

Kurian adds, “We showed the world that big infrastructure projects like [Cochin] Airport can be put into operation fully using alternative energy sources.”  . This will also avoid CO2 emissions by more than 9 lakh metric tons over the next 25 years, which is equivalent ot  planting 90 lakh trees or not driving 2,400 million miles “.  (Lahk is another unit in Indian counting, one lakh equal to 150,000.  90 lakh trees would be 13,500,000 trees –a  substantial number.)

Feeding the airport’s workers from the under-solar-panel gardens while having enough food left to sell to incoming passengers and generating all the power necessary to operate a large airport should give managers worldwide impetus to examine this new option.

If this were augmented with electric taxiing systems, such as those developed by Safran and L3, could further use solar-generated, scalable electric supplies to offset the need for expanded grids and added fuel burdens.


Growing plants next to and under the solar panels at the airport boosts overall productivity reports that, “It’s the latest example of how panels can work to help crops grow, a field known as “agrophotovoltaics.” Researchers from Germany’s University of Hohenheim ran an experiment in 2017 where they placed 720 solar panels in scaffolds above a series of crops. The crops tended to grow slower, with potatoes around 18 percent slower, but the yields were still profitable, the panels offset the electricity costs, and the setup increased land use efficiency by 60 percent:”

Profits should increase in the future as the cost of solar panels decrease.  For now, Cochin Airport and its leadership are showing a way to make airports a viable part of the communities they serve.


Structural Battery Doubles Flight Time

Structural batteries, structures which are also their own energy storage devices, are being looked at with increasing frequency.  Your editor has long been a proponent of integrating aircraft structures and the means of generating, storing and releasing energy – something he calls “the Grand Unified Airplane.”  Joe Faust, a hang glider pioneer and designer of energy-gathering kites, put the idea of including batteries in an airplane’s structure into your editor’s mind.  This video from the 1970’s shows Joe was not only athletic and adventurous – he was clean.  His Wikipedia page is even more fascinating.

40 Years Later at Case Western

Following Joe Faust’s lead, Case Western professor Vikas Prakash has demonstrated the potential or structural energy storage at model size.  In what was described as an “otherwise unremarkable” craft, Prakash inserted “structural battery” components inside the six-foot wingspan on his unmanned aerial vehicle (UAV).

Pre- insertion, the craft had been able to fly for 91 minutes before the batteries died.  After the structural insertion, it managed 171 minutes without a recharge.*  The other immediate benefits of  such integration include having more fuselage space for larger payloads and a better load distribution in the wings themselves – making for a stronger airframe.  Case Western’s releases don’t mention battery types or how they are incorporated as part of the structure, but if weight remains equal, the enhanced flight duration is a solid achievement.

Dr. Prakash works with Event 38, an Akron-area drone company, and a commercial partner on this battery project, which “builds fixed-wing, unmanned aircraft for mapping and surveying applications. The company has customers in 40 countries who primarily use the drones for agriculture or construction purposes.”

Jeff Taylor of Event 38 and Dr. Prakash of Case Western prepare drone for flight

Jeff Taylor, CEO of Event 38, was on hand to launch the demo flight.  He explained, “The new structural battery system offers benefits that will appeal to our customers.  The more efficient battery opens the door to build craft with more complex and sensitive sensors that small drones usually struggle to carry.”

The small drone will carry cameras for surveillance, but scaling the basic design up would eventually enable carrying larger cargo and even passengers.

Dr. Prakash foresees regional electric jets able to carry passengers and cargo and compete in terms of speed and distance with their fuel-burning competition.

Funding and Collaboration

His latest work is related to the NASA project conceptually and is funded by the Partnership for Research in Energy Storage and Integration for Defense and Space Exploration (PRESIDES) program. That partnership is sponsored by the Ohio Federal Research Network (OFRN) and managed by the Great Lakes Energy Institute at Case Western Reserve.

A large team and support vehicle for a small drone. Photo by Mark Haberbusch, PRESIDES, GLEI

The two-year, $450,000 project, officially known as “Hi-Performance Multifunctional Structural Energy Storage,” is one of 22 OFRN applied-research projects in the state, all of which emphasize collaboration among research universities, government and private companies.

“This new battery has a real chance to improve the day-to-day operations of our federal partners, and it has clear commercial applications,” OFRN Executive Director Dennis Andersh said in a statement. “We are proud to have enabled and supported this type of successful collaborative research.”

*(Repeat of a Self-serving Advertisement – Warning: Your editor has an article in the July, 2013 issue of Kitplanes magazine called, “The Grand Unified Airplane,” which details how materials science could lead to aircraft that ultimately  take their power from the “very act of flight itself.”  Dr Prashak’s work certainly points to one way this could happen.)


Mary Grady, A Great Aviation Journalist

I met Mary Grady at the 2011 Sun ‘n Fun Flyin in Lakeland, Florida.  After that, she and I swapped tips and leads for articles.  Her work at AVweb and for Belvoir Publications was professional and polished – always.  I’m using AVweb’s tribute to her, especially since it shows her many facets.  She will be missed.

Dean Sigler

Mary Grady, one of AVweb’s longest-serving, most dedicated and respected contributing editors, died at her home in Warwick, Rhode Island, on March 12 after a long illness.

Mary was one of the founding members of the internet experiment that became AVweb and continued as a key staff writer until her health challenges prompted a leave of absence earlier this year. She worked for AVweb for 20 years and wrote thousands of articles. To the best of anyone’s recollection she never missed a deadline.

“Mary had a quiet strength in her professional skills, but also in the way she carried herself,” said Tim Cole, AVweb’s editorial director. “When deadlines loomed or big, late-breaking stories came knocking, Mary was the calm, reliable, get-it-done pro in the eye of the storm. We depended on her for everything, and will go forward trying to live by her example.”

In her long career, she covered the full gamut of aviation stories from balloons to supersonic aircraft and did so with precision, clarity and balance. She was especially interested in new innovations that made aviation more accessible, safer and more environmentally responsible. She also covered aviation for Robb Report.

Mary was born in Providence, the capital of her beloved Rhode Island, in 1955 and spent most of her life there, most recently at her home a few steps from Narragansett Bay. She was a passionate environmentalist and was an adjunct professor of geography and environmental science at Rhode Island College. In her “other” journalism career, Mary won numerous awards for environmental reporting and was the author of three books.

But journalism was just an expression and outlet for Mary’s passion to learn, discover, explore and teach. After graduating college in Rhode Island, she obtained a Master’s Degree in Geography in Hawaii. She obtained her balloon and private pilot certificates and worked as an instructor on both in California and Florida. She was also a sailing instructor on the Tall Ship Rose, a replica of an 18th century Royal Navy frigate. Private services are planned.


Silicone Wrinkles Can Be Beautiful

Hanqing Jiang, a professor in ASU’s School for Engineering of Matter, Transport and Energy, has come up with a clever and inexpensive way to fight dendrites in lithium batteries.  Since these spiky little outbreaks can lead to battery fires, his team’s findings might lead to safer batteries.  The approach involves silicone.

Many of us put up a (usually futile) fight against wrinkles, our youth culture spending fortunes to avoid the inevitable.  Scientists at Arizona State University, however, are encouraging wrinkles in their lithium-metal batteries, and pouring cheap silicone goo over their anodes to discourage dendrites from popping up.

This novel approach to crafting lithium metal anodes for batteries is something Arizona State University scientists are working on, with surprising results.  Hanqing Jiang, a professor in ASU’s School for Engineering of Matter, Transport and Energy, in the Ira A. Fulton Schools of Engineering

 Silicon or Silicone?

Live Science explains an important distinction.  “In short, silicon is a naturally occurring chemical element, whereas silicone is a synthetic substance.

“Silicon is the 14th element on the periodic table. It’s a metalloid, meaning it has properties of both metals and nonmetals, and is the second most abundant element in the Earth’s crust, after oxygen.

“Silicon readily bonds with oxygen and is rarely found in nature in its pure form. You’ve likely seen silicon as silicon dioxide or silica, better known as quartz, which is the most common component of sand.”

That it also makes up a major part of glass and computer chips shows the versatility of this common element.

Silicone, on the other hand, combines silicon with oxygen, carbon and hydrogen to make “generally a liquid or… flexible, rubberlike plastic” we use to calk our windows or enhance our trophy wives.

Reducing Stress

When lithium metal is deposited onto a rigid surface (the orange surface above), compressive stresses are formed, which cannot be relaxed and dendrites form (Image source: Arizona State University)

 Dr. Jiang’s research at ASU may help lithium metal anodes keep their cool in batteries while doubling the energy storage capacity over carbon-based anodes used in many (most?) of today’s lithium ion cells.

Plating of the lithium metal onto the silicone (PDMS) substrate causes it to wrinkle in 2 dimensions, reducing the lithium metal residual stress and dendrite formation (Image source: Arizona State University)

Beginning by depositing a layer of lithium metal onto a soft substrate of polydimethylsiloxane (PDMS or silicone) researchers then observed wrinkles forming in the silicone.  According to ASU, “When the lithium metal was deposited on the silicone substrate, the stresses created by the accumulation of the metal were relieved by the formation of wrinkles in the silicon substrate. The elimination of the residual stresses had a large effect on the dendrites. ‘There were remarkable reductions in dendrite growth,’ said Jiang. The research team discovered that the reduction in dendrite growth was directly related to the reduction in stress caused by the deformation and wrinkling of the silicon substrate.”

Dr. Jiang explained the significance of the reaction. “We already know that tiny tin needles or whiskers can protrude out of tin surfaces under stress, so by analogy we looked at the possibility of stress as a factor in lithium dendrite growth.”

3D Equals Longer Life

The team found that giving the silicone a three-dimensional form, “almost like a sponge,” relieved stress and effectively inhibited dendrite growth.  Jiang compares the form to a sugar cube, with PDMS forming a continuous network as the substrate covered by a thin copper layer to conduct electrons.  Lithium fills these pores.

Zinc, sodium, and aluminum batteries have the same tendency to form dendrites, so the use of silicone could help develop safe, high-energy density batteries with several other metals .

 The Team’s Paper

Xu Wang,  Wei Zeng,  Liang Hong,  Wenwen Xu,  Haokai Yang,  Fan Wang,  Huigao Duan,  Ming Tang and Hanqing Jiang participated in the research.  Their paper, “Stress-driven lithium dendrite growth mechanism and dendrite mitigation by electroplating on soft substrates,” appeared in the March 6, 2018 issue of Nature Energy.

The abstract for the team’s paper gives an introduction to their research and hints that their approach results in enhanced performance and  great longevity for batteries using their technique.

“Problems related to dendrite growth on lithium-metal anodes such as capacity loss and short circuit present major barriers to next-generation high-energy-density batteries. The development of successful lithium dendrite mitigation strategies is impeded by an incomplete understanding of the Li dendrite growth mechanisms, and in particular, Li-plating-induced internal stress in Li metal and its effect on Li growth morphology are not well addressed. Here, we reveal the enabling role of plating residual stress in dendrite formation through depositing Li on soft substrates and a stress-driven dendrite growth model. We show that dendrite growth is mitigated on such soft substrates through surface-wrinkling-induced stress relaxation in the deposited Li film. We demonstrate that this dendrite mitigation mechanism can be utilized synergistically with other existing approaches in the form of three-dimensional soft scaffolds for Li plating, which achieves higher coulombic efficiency and better capacity retention than that for conventional copper substrates.”

Researchers included scientists from Rice University and Hunan University, China.  Funding was provided in part by the Department of Energy.


Mixing It Up With MXene

Over the years reporting on battery developments, we’ve seen paper batteries, spray-on batteries, structural batteries and many types of material mixes.  Drexel University has tossed all the above intone big hopper and come up with MXene, a potentially dynamic way of making batteries, supercapacitors, antennas, and structural elements that can be conductors, semiconductors, and insulators, among myriad applications.

Going Through a Phase

MXenes are formed from layered MAX phases, defined by Drexel as forming, “A large family of ternary(composed of three) carbides with the general formula Mn+1AXn, where n = 1–3, M is an early transition metal, A is an A-group element (mostly IIIA and IVA), and X is C and/or N:”  That level of chemistry is two quantum leaps above your editor’s pay grade, so you’ll have to work out the implications for yourself.

peeling layers from the MAX phase produces specific characteristics for new materials.  Mixing this with the MXene slurry enables a protected anode

Or, you can read the more understandable explanation in this link.

Drexel explains, “MXenes are made by chemically etching a layered ceramic material called a MAX phase, to remove a set of chemically-related layers, leaving a stack of two-dimensional flakes. Researchers have produced more than 30 types of MXene to date, each with a slightly different set of properties.”

The research group Used two of them the to make  the silicon-MXene anodes for testing: titanium carbide and titanium carbonitride.   Researchers made another anode from graphene-wrapped silicon nanoparticles. “All three anode samples showed higher lithium-ion capacity than current graphite or silicon-carbon anodes used in Li-ion batteries as well as superior conductivity. The silicon-MXene anodes had on the order of 100 to 1,000 times higher conductivity than conventional silicon anodes.”

Good for Mass Production

“The continuous network of MXene nanosheets not only provides sufficient electrical conductivity and free space for accommodating the volume change but also well resolves the mechanical instability of Si,” according to the researchers. “Therefore, the combination of viscous MXene ink and high-capacity Si offers a powerful technique to construct advanced nanostructures with exceptional performance.” The process of slurry-casting MXene-silicon anodes is scalable for mass production of anodes of any size, which means they could make their way into batteries that power just about any of our devices.”

Scanning electron microscope (SEM) view of MXene layers

Researchers found that slurry casting prevented the silicon anode from expanding to its breaking point, something other researchers have attempted for the last decade. Unrestrained, silicon can expand as much as 300 percent, which can cause it to break and  make the battery malfunction.  Excellent mechanical strength in the silicon-MXene anodes holps hold things together.  The anodes “are quite durable up to 450 microns thickness.”

This could expand the charge-to-charge life of cell phones and electric cars by as much as 40 percent, according to researchers from Drexel and Trinity College in Ireland.  “Silicon anodes are projected to replace graphite anodes in Li-ion batteries with a huge impact on the amount of energy stored,” said Yury Gogotsi, PhD, Distinguished University and Bach Professor in Drexel’s College of Engineering and director of the A.J. Drexel Nanomaterials Institute in the Department of Materials Science and Engineering, who was a co-author of the research. “We’ve discovered adding MXene materials to the silicon anodes can stabilize them enough to actually be used in batteries.”

You can see Dr. Gogotsi’s recent presentation in Spain below.

Researchers found that slurry casting prevented the silicon anode from expanding to its breaking point, something other researchers have attempted for the last decade. Unrestrained, silicon can expand as much as 300 percent, which can cause it to break and  make the battery malfunction.  Excellent mechanical strength in the silicon-MXene anodes holps hold things together.  The anodes “are quite durable up to 450 microns thickness.”

This could expand the charge-to-charge life of cell phones and electric cars by as much as 40 percent, according to researchers from Drexel and Trinity College in Ireland.  “Silicon anodes are projected to replace graphite anodes in Li-ion batteries with a huge impact on the amount of energy stored,” said Dr. Gogotsi,  who was a co-author of the research. “We’ve discovered adding MXene materials to the silicon anodes can stabilize them enough to actually be used in batteries.”  Lead author Chuanfang (John) Zhang from Trinity College, Ireland submitted the paper, “High capacity silicon anodes enabled by MXene viscous aqueous ink,” to Nature Communications, where it was published on February 20, 2019.


Goodyear AERO Wheel Sparks Controversy

Goodyear Creates a Flying Tire

Displayed this week at the Geneva Auto Show, Goodyear’s new AERO wheel is not just rolling stock, but a possible aeronautical device that could propel a “flying car” skyward.  Not only could it roll along the freeway, it could navigate the vehicle and choose whether to be in highway or aerial mode.  These smart tires could have some problems, though, that could negate their aerial potential, according to some critics.

Goodyear’s press release extols the possible virtues of the forward-thinking product: “GENEVA, March 5, 2019 /PRNewswire/ — The Goodyear AERO concept is a two-in-one tire designed for the autonomous, flying cars of the future. This concept would work both as a tire for driving on the road and a ‘propeller’ for flying through the sky.”

Chris Hensel, Goodyear’s Chief Technology Officer, explains: “For over 120 years Goodyear has obsessively pursued innovations and inventions, partnering with the pioneers driving change and discovery in transport.  With mobility companies looking to the sky for the answer to the challenges of urban transport and congestion, our work on advanced tire architectures and materials led us to imagine a wheel that could serve both as a traditional tire on the road and as a propulsion system in the sky.”

Loaded with Tech

Goodyear promotes five functions the “purely conceptual” AERO wheel can accomplish.

Its multimodal design would enable the wheel to serve as a road-based drive train, absorbing forces from the road in a vertical orientation and act as a lifting propulsor in horizontal orientation.

Non-pneumatic tire on flexible rims strong enough to act as rotors – a heady challenge

Its non-pneumatic structure’s spokes would provide support as a wheel and act as fan blades when the tire is tilted.  This would require an ability to support the vehicle’s weight in several planes and absorb shocks when on the road.

Goodyear says the wheel would be driven by magnetic propulsion, presumably like a hub motor.

The AERO would use light-based, fiber optic sensors to monitor road conditions, tire wear and the structural integrity of the tire itself.

This is the first smart wheel your editor has encountered, the AERO wheel featuring an embedded artificial intelligence processor that would use data from the vehicle’s on-board sensors and from external vehicle-to-vehicle and vehicle-to-infrastructure communication.  The A.I. processor would select routes and choose whether the vehicle would roll or fly – a no-brainer for most pilots.

Serrated rims might reduce noise from fast-spinning wheel/rotor. Will these be the loudest things on the road or in the sky?

Goodyear’s Helsel concludes,  “Goodyear’s concepts are meant to trigger a debate on the tires and transport technologies for a new mobility ecosystem.”

Triggering a Debate

And that seems to have occurred, some fairly controversial views surfacing in the wake of the announcement.  Autoblog noted the similarity of Goodyear’s vision to the film Elysium, with the least among us living in, ”An above-ground landfill filled with grimy famine and high-tech, or [the well off in] a cyber-Bambi Shangri-La drowning in sunshine, leisure time, and ribbons of glass road.”

Autoblog notes the technical cleverness of the design and concludes, “Bring on Elysium already.”  How this level of luxury will be made available to all is probably a moot question.  Economists suggest we might all have to settle for a little less for everyone to have enough – but in the current political atmosphere, that might smack of socialism and not economic reality.

David Freeman, writing for NBC News, takes a somewhat contrary view on the tech front, interviewing Embry Riddle aeronautical University’s Pat Anderson, director of the Eagle Flight Research Center.  Anderson  notes the combination wheel/rotor might reduce parts count, but adds, “Combining things typically results in a lot of compromises.”

Anderson questions the slick transition from ground to aerial transport.   “’The downwash from the fast-spinning tire in flight mode might damage things below and possibly cause ‘horrific’ noise levels,” Anderson added. And he questioned why travelers would want to drive at all when they could fly. ‘I would just fly to where I wanted to park,’ he said.”

He is countered by Ella Atkins, a professor of aerospace engineering at the University of Michigan.  “In an email to NBC News MACH, she called the tire ‘innovative,’ adding, ‘It would be great to use the same transmission to turn the thrust-generating blades in flight mode that turns the rolling wheels in car mode.’”

She did question the use of solid rubber tires, which reminded her of “the early days of automobiles.”  She asked, “How safe and efficient can a car be with ‘Model T tires’ in car mode even with 21st Century sensors and electronics?”

NBC explains that the AERO is not Goodyear’s first foray into radical tire design.
In recent years the company has developed concepts for an electricity-generating tire and a spherical tire capable of rolling in all directions.

Whether the AERO of other Goodyear designs end up driving us or flying us to our future destinations remains to be seen.  Innovations usually come hard, but we encourage them for making us break from the obvious and hackneyed.


Metro Hop Leaps From Tall Buildings

Metro Hop™ is an electric, conventional fixed wing, all-weather aircraft designed to operate within the urban air mobility environment, according to their web site.

Different Design Philosophies

Metro Hop is a unique view from the leaders of the CAFE Foundation, which is often allied with the Vertical Flight Society.  Metro Hop’s fixed-wing approach seems to fly in the face of the team’s normal affiliations.

The Sustainable Aviation Foundation was established as a proponent of fixed-wing design by President Brien Seeley, and promotes “pocket airparks,” small urban and suburban airports that would distribute availability of short-range aircraft within walking or cycling distance for many urban dwellers.  CAFE would distribute spaces similar to heliports on rooftops or on specialized buildings such as those envisioned by Uber as part of its LIFT program.

Metro Hop, according to the development group, would cruise at 400 kilometers per hour (250 mph) and carry two passengers.  Using current battery technology, it would have a 160 kilometer (100 mile) range, enough for in-city hops in the largest urban areas.  It near-silent operations would be imperceptible against the normal city background noise, allowing day and night operation.

Its spring-loaded  landing gear will keep passengers from bouncing around on takeoff and landing, even though it provides a bounce on departure.  Powered wheels will enable climbs and descents from and to the service area below the landing platform, although passengers might find the squeamish part of the flight is the descent from the landing platform.

According to Metro Hop, “Urban air mobility means a safe, efficient, community-accepted method of moving people and cargo via aircraft within cities.”  The firm will attempt to operate out of its own unique Skyport stations on or near “prime urban locations,” providing the mobility that ground transport often fails to deliver.

Metro Hop uses not only existing battery technology, but follows a “well-known flight envelope, and a clear path to certification,” according to company leaders.  Their hope is that it would make a trillion-dollar industry possible, operate on $39 fares and make itself “a commonplace tool for any business, large or small.

Bruno Mombrinie and an Inventive Streak

One of the founders of Metro Hop, Bruno Mombrinie has a history of mechanical design, having a degree in mechanical engineering from MIT.  He helped build the Chrysalis human powered airplane, even getting to fly the featherweight biplane several times.  He recalls the feelings that experience drew from him.  “The feeling of being so, so high (39ft)…to fly under my own power was beyond…I just wanted to burst…actually I was so out of breath from the effort, I could hardly mouth ‘yippee!'”

Bruno Mombrinie took the picture of another student flying MIT’s Chrysallis HPA.  A clever photo edited inserted Bruno’s image chasing the airplane

He went on to found AVEC Scientific Design, specializing in disposables for operating rooms, and has a medical device for children with spinal cord injuring awaiting FDA approval.  He even designed the world’s lightest and stiffest bicycle crankset, which helped Lisa Vetterlein set a woman’s human powered vehicle land speed record of 66.65 mph.

Whether we will see hundreds of Metro Hops wending their way over the skies of San Francisco will depend, as all great ideas do these days, on finding venture capitalists willing to back the enterprise.


Is Ionic Propulsion Plausible?

Ethan Krauss responds to MIT’s Ionic Flyer Coverage

There seems to be great interest in ionic propulsion.  After we published “MIT’s Ionic Flyer – Solid State All the Way,” our editorial offices (otherwise known as your editor’s kitchen) received a comment from Ethan Krauss, who corrected the historical record.  He explains, “MIT was NOT “the first ion propelled aircraft of any kind to carry their power supply, as their video and paper say.  They don’t use less voltage, they are not more efficient, they are not the largest. Size was not the limit in the past.”

Click on image to see video of MIT’s first flights.

“They are the second in the world to be able to claim that they built an ion propelled craft that can carry its power supply. Their craft however, was launched with the assistance of a bungee cord, and large wings thereby reducing the power needed for its 10 second flight.”

The Cleveland Plain Dealer interviewed Mr. Krauss and reported: “‘Aviation started here in Ohio by two guys that everyone thought were just out of their minds,” Ethan Krauss said.  You could call Krauss, who is an electrical engineer, a modern-day Wright brother…. If you can move the air downwards without stirring it up too much, then you end up with a very efficient flying machine,’ Krauss said.  ‘The flying machine has no moving parts, it’s silent and creates no emissions. Possibly be a revolution in flight for light duty applications,’ said Krauss.”

Krauss responded to questions from your editor about whether a larger (say, person carrying)ionic propulsion lifting device could be powered by similar means.  “It is simply not correct to imply that lightweight lifters could carry their power supplies. The whole point is to be able to carry a power supply using ion propulsion. The power to weight ratio was 3 orders of magnitude too low. A larger heavier ion propelled device than MIT’s was flown in 2003 with an external power supply though.

“The first solely ion propelled aircraft to carry its power supply, is covered under US Patent No. 10,119,527. This patent covers all ion propelled aircraft that carry their power supplies against gravity since 08/07/2014. Here is the website with videos that show it fly for around 2 minutes:”

“The first and only ion propelled invention ever that can both take off and fly with onboard power, is called the ‘Self Contained Ion Powered Aircraft.’  It is extremely well verified to predate the MIT device with onboard power. It also produces about 20 times as much thrust for its weight. ”

The patent,  provides details of how Krauss’s machine is constructed and how it works.

“In accordance with an aspect of the present invention, a self-contained ion powered aircraft assembly is provided. The aircraft assembly includes a collector assembly, an emitter assembly, and a control circuit operatively connected to at least the emitter and collector assemblies and comprising a power supply configured to provide voltage to the emitter and collector assemblies. The assembly is configured, such that, when the voltage is provided, the self contained ion powered aircraft provides sufficient thrust to lift each of the collector assembly, the emitter assembly, and the control circuit against gravity.

“In accordance with another aspect of the present invention, an ion powered aircraft assembly includes a collector assembly comprising at least three substantially concentric conductive elements, an emitter assembly, and a control circuit operatively connected to at least the emitter and collector assemblies and comprising a power supply to provide voltage to the emitter and collector assemblies.

“In accordance with yet another aspect of the present invention, an ion powered aircraft assembly includes a collector assembly, an emitter assembly, and a control circuit operatively connected to at least the emitter and collector assemblies. The control circuit includes a power supply configured to provide voltage to the emitter and collector assemblies and a resonant transformer that is continuously driven at an associated resonant frequency to provide a high voltage signal to another component of the control circuit.”

For Those Who Want One

A basic device, powered by an external source, can be assembled from balsa wood and aluminized Mylar film. These have been floating around in laboratories for several years, and are realizable for an enthusiast.

Skip the first minute or so, but then this video gets down to business.

These demonstrations illuminate a reality that ionic propulsion devices can fly, but questions remain as to whether these craft can be made into practical people or cargo carriers.  As they grow large enough and carry enough voltage and amperage to lift more substantial loads, will there be a substantial danger in their passage?  Things at such light weight and high voltages seem dicey at best. reports about MIT’s efforts: “One of the first prototypes of the plane fried itself due to its black coating, as black color contains carbon, which conducts electricity. Those previous prototypes only managed to tumble to the ground seconds after being launched.

“The latest prototype, this time painted yellow, managed to sail through the air for almost 200 feet at 11 miles per hour (17 kilometers per hour). Unfortunately, it crashed into the nearest wall, but the fact still remains that the yellow prototype, dubbed simply Version 2, worked.”

As teams progress on their different paths, we might see some hope for more practical demonstrations of an interesting technology here on earth, rather than in propelling payloads toward Andromeda.


Purdue Flow Battery: Safer, Less Expensive

Promising enough to catch NBC’s attention, new flow battery technology from Purdue University promises quick refueling and up to 3,000 miles range in the electric car of the future.  If volumetric and gravimetric factors can be brought into line, this could be a useful energy storage medium for future aircraft.

John Cushman, Purdue University distinguished professor of earth, atmospheric and planetary sciences and a professor of mathematics and partner Eric Nauman, professor in mechanical engineering, biomedical engineering, and in basic medical sciences, co-founded IFBattery Inc.  The pair developed a “safe and affordable” patented technology that requires replacing fluids in their battery every 300 miles, and then swapping the anode material every 3,000 miles “taking less time than is needed to do and oil change” and costing about $65.  This calculates to about 2.167 cents per mile, considerably less than the 11 cents per mile your editor’s small econobox requires just for fuel.

Cushman further explains the economics from the infrastructure perspective: “It’s a game-changer for the next generation of electric cars because it does not require a very costly rebuild of the electric grid throughout the US.  Instead, one could convert gas stations to pump fresh electrolyte and discard depleted electrolyte and convert oil-changing facilities to anode replacing stations. It is easier and safer to use and is more environmentally friendly than existing battery systems.”

Furthering the use of repurposed service stations, IFBattery’s would be collected and taken to a solar farm, wind turbine installation or hydroelectric plant for recharging.  Cushman says, “It is the full circle of energy with very little waste.  IFBattery’s components are safe enough to be stored in a family home, are stable enough to meet major production and distribution requirements and are cost-effective.”

Economically, the system would have a “flow” of materials at the infrastructure level.  Cushman explains, “Instead of refining petroleum, the refiners would reprocess spent electrolytes and instead of dispensing gas, the fueling stations would dispense a water and ethanol or methanol solution as fluid electrolytes to power vehicles.  Users would be able to drop off the spent electrolytes at gas stations, which would then be sent in bulk to solar farms, wind turbine installations or hydroelectric plants for reconstitution or re-charging into the viable electrolyte and reused many times. It is believed that our technology could be nearly ‘drop-in’ ready for most of the underground piping system, rail and truck delivery system, gas stations and refineries.”

As to safety, Michael Dziekan, senior engineer for IFBattery, adds a significant set of numbers to the discussion. “The battery does two things: it produces electricity and it produces hydrogen. That is important because most hydrogen-powered cars run on a 5,000 or 10,000 PSI [pounds per square inch] tank, which can be dangerous.  This system generates hydrogen as you need it, so you can safely store hydrogen at pressures of 20 or 30 PSI instead of 10,000.”

Eric Nauman, Purdue University professor in mechanical engineering and in basic medical sciences and co-founder of IFBattery, and Michael Dziekan, senior engineer for IFBattery, run tests on a membrane-free, flow battery being used to power a golf cart. The battery has the potential to generate enough energy to drive an electric car up to 3,000 miles.  Image courtesy Purdue University

Because the single-fluid technology does not use a membrane or separator, and oxidizes the anode to produce electrons, and reduces the fluid at the cathode, it generates current to power vehicles.  The oxidant is a macro-molecule that lives in the electrolyte, but is reduced only at the cathode.

First tested in scooters and then larger off-road vehicles, the technology will next be tested in industrial equipment and then automobiles, according to Cushman.  He points out, “Historically, flow batteries have not been competitive because of the low energy density.  For example, conventional flow batteries have an energy density of about 20 watt hours per kilogram. A lithium-ion battery runs on 250 watt hours per kilogram. Our flow battery has the potential to run between three and five times that amount.”

John Cushman, Purdue University distinguished professor of earth, atmospheric and planetary science and a professor of mathematics, is commercializing a technology that could provide an “instantly rechargeable” method forelectric and hybrid vehicle batteries through a quick and easy process similar to refueling a car at a gas station. Image courtesy Purdue University

“We are at the point now where we can generate a lot of power. More power than you would ever guess could come out of a battery like this,” Cushman said.

Naumann adds, “Conventional electric cars like Tesla have lithium-ion batteries that are usually plugged in overnight. Our flow battery uses a water-based single fluid that can run the car like it is a gas engine except it is not burning anything – it’s like a hybrid of a battery and a gas.”

According to Purdue, “Cushman will present the technology at the 11th annual meeting of InterPore in Valencia Spain, in May 2019 and he previously presented at the International Society for Porous Media 9th International Conference in Rotterdam, Netherlands and its 10th International Conference in New Orleans.”

IFBattery licensed part of the technology through the Purdue Research Foundation Office of Technology Commercialization and has developed patents of its own.

The technology aligns with Purdue’s Giant Leaps celebration of the university’s global advancements made in health, space, artificial intelligence and sustainability as part of Purdue’s 150th anniversary. Those are the four themes of the yearlong celebration’s Ideas Festival, designed to showcase Purdue as an intellectual center solving real-world issues.

One hopes that this battery can be sized for practical vehicular use and that the costs of converting existing gas stations will not prevent its expansion into real-world use.  Refills at 300 miles and changing out electrodes at 3,000 miles is not an onerous cost for clean operation. It reminds your editor of refills of his car, back in the day, and swapping out points and plugs.  Younger drivers might look up that maintenance necessity in old maintenance manuals.