Hydrogen Cars – How do Fuel Cells Really Work? Where do they fit into the Alternative Fuel Plan? Will they Prove to be the ‘Ultimate’ Renewable Fuel?


Many project hydrogen as the ultimate alternative fuel, but how does it stack up now and in the future?

In the conversation of sustainable motoring, there has long been a quiet alternative to electricity as a propulsion for our cars – hydrogen. Projected by many as a no-compromise alternative fuel that just needs more development, the reality is somewhat more complicated.

Manufacturers are persisting regardless, with Toyota, Honda and Hyundai all at the forefront of the technology in 2021.

Its future in locomotive and long-haul trucking will almost certainly drive its continued development, and as the technology matures further some have started thinking about its applications in future motorsport – an offshoot from the main technological drive that could make it viable, and crucially more entertaining than racing EVs.

What is hydrogen fuel, and how does it work?

As the most abundant element in the universe, hydrogen is a great place to start when it comes to using it as fuel. Yet while sourcing it isn’t an issue, the process of turning it into useable fuel is where the complexity lies. For use in cars, hydrogen needs to be turned into its liquid form, which requires it to be compressed and kept at cryogenic temperatures.

This process is both energy intensive and expensive, which is where the practical realities of its commercial use come into question. As it stands, the production of compressed hydrogen is more energy and carbon intensive than what it gives back during the ‘burn’, but this process is being continually refined and improved. Soon, there will be a Europe-recognised certification of ‘Green Hydrogen’, which will guarantee the carbon neutrality of its production.

There are also many entirely different ways that hydrogen can create energy and thus drive cars, further complicating the technology. For the sake of simplicity let’s focus on the main two: hydrogen combustion and hydrogen fuel cells.

Hydrogen combustion

Hydrogen combustion works, as its name suggests, in exactly the same way as fossil fuel combustion engines, but without the carbon emissions. It sounds perfect, in theory, but the reality is quite different. In this process, liquid hydrogen is stored in an insulated and pressurised tank where it is injected directly into the cylinders at high pressure, burning in the same four-stroke cycle as a normal petrol engine.

Running fuel in a pressurised circuit is not the issue – cars that burn compressed natural gas are common in Australia and Brazil. Rather it lies in compressed hydrogen’s poor energy density, which makes it burn very inefficiently. BMW developed a limited-run version of a 7-seriesback in 2002 with a V12 engine converted to run on liquid hydrogen, but its fuel consumption was rated at around 50l/100kms or 4.7mpg, around four times higher than that of its petrol V12 counterpart.

From an emissions perspective, the carbon footprint of producing that much fuel is extremely high per kg, which more than counteracted its lack of a CO2 output at the exhaust pipe. And there is another long-standing issue associated with burning liquid hydrogen, as while it may not produce CO2, it does still produce large amounts of nitrogen oxide (NOx), or more specifically the nasty greenhouse gas associated with VW’s dieselgate emissions scandal.

Hydrogen cars – cutaway

Hydrogen fuel cells

Hydrogen fuel cells, by contrast, don’t burn liquid hydrogen, but create electricity from it by a completely different method.

Rather than using any form of combustion engine, hydrogen fuel cell vehicles use the process of electrolysis to create electricity, which feeds a battery and then an electric motor.

As well as being far more efficient per unit of liquid hydrogen than quite literally setting it on fire in a combustion process, a fuel cell also produces no harmful NOx emissions. This, in theory, combines the benefits of EVs and combustion engines, with the former’s lack of harmful emissions and the latter’s fast fill time come refuelling.

The drawbacks once again come from the process of creating the liquid hydrogen, before taking into account the relative complexity and expense of having what is essentially a tiny atom-splitting power station on your driveway.

As battery technology continues to grow in leaps and bounds, the benefits of a quick fill time will also become less of a drawcard.

This hasn’t stopped manufacturers such as Hyundai and Toyota from persisting with hydrogen fuel cells, exemplified by the all-new second-generation Toyota Mirai and Hyundai Nexo. So while your next car is far more likely to be electric than hydrogen, it certainly will have its place in the wider ecosystem.

Hydrogen cars – mirai engine bay

Motorsport and combustion engines

For those of us skeptical about the reality of carbon-neutral motor racing, hydrogen does offer another alternative to traditional eFuels as a clean fuel source for the continuation of motorsport and combustion engines.

While widespread applications of hydrogen combustion engines make little commercial sense, the ability to run racing engines on liquid hydrogen could be a possibility in future.

Toyota is already experimenting with the technology, running a converted Corolla racing car in the Japanese Super Taikyu Series in 2021. As mentioned above, the lack of carbon emission is the obvious reason to apply this technology, although Toyota has not approached the issue of NOx.

Luckily, technology to remove nitrogen oxide from exhaust gases has been underpinned by advances in diesel technology of all places, utilising AdBlue technology, or a mixture of urea and deionised water, to remove NOx before it reaches the end of the exhaust pipe.

Read the Top 4 Articles from Genesis Nanotech This Week Like: New MIT Nano-Kevlar – Hydrogen Fuel from the Sea + More …


An Alternative to Kevlar – MIT and Caltech Create Nanotech Carbon Materials – Can withstand supersonic microparticle impacts

New Nanoscale Material Harvests Hydrogen Fuel From the Sea – University of Central Florida

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Engineers Develop a Simple Way to Desalinate Water Using Solar Energy – Reduced Costs + 4X Production Volume

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Hydrogen Powered Fuel Cell EV’s? Or Battery Powered EV’s? Toyota is Placing a Bet on the Green Future

Engineers Develop a Simple Way to Desalinate Water Using Solar Energy – Reduced Costs + 4X Production Volume


Alharbawi Naseer Tawfiq Alwan assembled a prototype of the distiller in the UrFU workshop. Credit: Ilya Safarov.

Distillation of water using solar energy is considered one of the most popular desalination methods today.

Power engineers at Ural Federal University (UrFU), together with colleagues from Iraq, have developed a new desalination technology, which is claimed to be much more effective than others, by incorporating a rotating cylinder.

The method proposed by the UrFU power engineers will significantly reduce the cost of desalination and will increase production volumes by four times.

The experimental new solar distiller incorporates a rectangular basin, inside of which is a horizontally oriented black steel cylinder. The basin is filled with undrinkable water, and the cylinder is slowly rotated by a solar-powered DC motor.

The rotating hollow cylinder inside the solar distiller accelerates water evaporation in the vessel by forming a thin film of water on the outer and inner surface of the cylinder, which is constantly renewed with each turn. As the film is so thin, the water film quickly evaporates due to the rapid transfer of heat from the surface of the cylinder to the adjacent water film. To increase the temperature of water under the cylinder, the engineers used a solar collector.

prototype was tested on a rooftop in the Russian city of Ekaterinburg for several months (June-October, 2019). As part of the experiment, the rotation speed of the cylinder inside the solar distiller was 0.5 rpm. This intensity and time are enough to evaporate a thin film of water from the surface of the cylinder.

The tests showed the high efficiency and reliability of the developed device. In addition, the scientists noted that the relatively high intensity of solar radiation and low ambient air temperature also contributed to the performance of water distillation.

Read more: Nanofiber membrane makes seawater drinkable in minutes

The performance improvement factor of the created solar distiller, compared to traditional devices, was at least 280% in the relatively hot months (June, July, and August) and at least 300% and 400% in the cooler months (September and October), at the same time, the cumulative water distillation capacity reached 12.5 l/m2 per day in summer and 3.5 l/m2 per day in winter,” commentedAlharbawi Naseer Tawfik Alwan, a research engineer at the Department of Nuclear Power Plants and Renewable Energy (UrFU).

The desalination technology created in the UrFU with a simple design and low cost may be especially in demand in the Middle East and Africa – in countries with a high potential for solar energy and a shortage of freshwater.

In the future, scientists plan to improve the technology and increase the performance of the solar distiller at the lowest possible capital and operating costs for different climatic conditions.

New Nanoscale Material Harvests Hydrogen Fuel From the Sea – University of Central Florida


Researchers developed a long-lasting, stable nanoscale material for electrolysis.

Researchers at the University of Central Florida (UCF) designed the world’s first nanoscale material capable of efficiently splitting seawater into oxygen and green hydrogen, which can be used as a fuel, a press release explains.

The development is another step towards improving our capacity for harvesting hydrogen fuel in a bid to fight climate change by reducing our reliance on fossil fuels.

The researchers detailed their long-lasting nanoscale material for electrolysis — the process of separating water into hydrogen and oxygen — in the journal Advanced Materials. According to study co-author Yang Yang, the new material “will open a new window for efficiently producing clean hydrogen fuel from seawater.”

There has been great debate in recent times over the feasibility of hydrogen fuel for helping to combat hydrogen fuel. Though Tesla and SpaceX CEO recently called the ideaof hydrogen cars “mind-bogglingly stupid,” companies such as Toyota and BMW have shown their support for the technology and are developing hydrogen fuel cell vehicles.

Meeting the rapidly growing requirement for green hydrogen

For their nanoscale material, the UCF researchers devised a thin-film material featuring nanostructures on its surface. In their study, the scientists explain that the material is made of nickel selenide with added, or “doped,” iron and phosphor. “The seawater electrolysis performance achieved by the dual-doped film far surpasses those of the most recently reported, state-of-the-art electrolysis catalysts and meets the demanding requirements needed for practical application in the industries,” Yang explained.

Nanoscale material catalyzing the electrolysis reaction. Source: University of Central Florida

They say that not only is their material effective at catalyzing the electrolysis process, it also shows the stability and high performance required to use the material at an industrial scale — they tested their material for over 200 hours and said it retained high performance and stability throughout the tests. Earlier this month, French firm Lhyfe announced it was commencing tests on the world’s first offshore green hydrogen plant, which will make use of the abundant surrounding water source and a nearby wind turbine.

Though there is still debate over the use of hydrogen fuel as opposed to electricity, we will be much better off in a world where hydrogen and electricity compete with each other, instead of with the current supremacy of the internal combustion engine.

An Alternative to Kevlar – MIT and Caltech Create Nanotech Carbon Materials – Can withstand supersonic microparticle impacts


So, nanotechnology. “Great Things from Small Things”. Really amazing stuff … really.

So amazing in fact, that some researchers and engineers at Caltech, MIT, and ETH Zurich have discovered how to make lighter than Kevlar materials that can withstand supersonic microparticle impacts.

What does all this mean for material science? A whole lot if you ask me. I mean, this is literally going to change to way we produced shielding of any kind, especially for law enforcement agencies. Hang on a second, I’m getting a little ahead of myself here. 

A new study by engineers at the above-mentioned institutes discovered that “nano-architected” materials are showing insane promise in use as armor. What are “nano-architected” materials? Simply put, they’re materials and structures that are designed from “precisely patterned nanoscale structures,” meaning that the entire thing is a pre-meditated and arranged structure; what you see is exactly what was desired. 

Not only this, but the material is completed from nanoscale carbon struts. Arranged much like rings in chainmail, these carbon struts are combined, layer upon layer to create the structure you see in the main photo. So yeah, medieval knights had it right all along, they just needed more layers of something that already weighed upwards of 40 lbs for a full body suit.

So now that the researchers had a structure, what to do with it. Why not shoot things at it? Well, like any scientists, pardon me, “researchers,” that have been cooped up in a lab for too long, that’s just what they did, in the process, documenting and recording all the results.

To do this, researchers shot laser-induced microparticles up to 1,100 meters per second at the nanostructure. A quick calculation and you’re looking at a particle that’s traveling at 3,608 feet per second. Want to know more? That’s 2,460 miles per hour! 

Two test structures were arranged, one with slightly looser struts, and the second with a tighter formation. The tighter formation kept the particle from tearing through and even embedded into the structure. 

If that’s not enough, and this is a big one, once the particle was removed and the underlying structure examined, researchers found that the surrounding structure remained intact. Yes, this means it can be reused.

The overall result? They found that shooting this structure with microparticles at supersonic speeds proved to offer a higher impact resistance and absorption effect than Kevlar, steel, aluminum, and a range of other impact-absorbing materials. The images in the gallery even show that particles didn’t even make it thirty percent of the way through the structure; I counted about six to seven deformed layers.

To get an idea of where this sort of tech will be taking things, co-author of the paper, Julia R. Greer of Caltech, whose lab led the material’s fabrication, says that “The knowledge from this work… could provide design principles for ultra-lightweight impact resistant materials [for use in] efficient armor materials, protective coatings, and blast-resistant shields desirable in defense and space applications.” 

Imagine for a second what this means once these structures are created on a larger scale. It will change the face of armor, be it destined for human or machine use, coatings, and downright clothing.

I’m not saying that suddenly we can stop bullets walking down the street, but it won’t be long until funding for large-scale production begins, and what I just said may become a reality. Maybe not for all people at first, but the military will definitely have their eye on this tech.

Submitted By Cristian Curmei

Could Form Energy’s “Iron-Air-Exchange Batteries” be the Holy Grail Answer to Large Scale Energy Storage? Ingredients? Rust And Salt


Form Energy Battery System Rendering. Courtesy Form Energy

Salt and rust – the bane of your car’s existence — may be the keys to storing enough renewable energy to power the electric grid for several days. That’s according to two local companies that have emerged with innovative battery designs based on cheap, widely-available materials.

After four years of stealth R&D, Somerville-based Form Energyhas emerged with what could be a breakthrough energy storage technology, based on rust.

Form Energy president and CEO Ted Wiley says the company has produced hundreds of working prototypes of an iron-air-exchange battery that can store large amounts of energy for several days.

“We’ve completed the science,” says Wiley, “what’s left to do is scale up from lab-scale protoypes to grid-scale power plants. “

In full production, “the modules will produce electricity for one-tenth the cost of any technology available today for grid storage,” Wiley says.

If the plan comes to fruition, Form Energy’s batteries could realize what’s called “the renewable energy Holy Grail” — relatively inexpensive, reliable grid-scale energy storage. Because solar and wind do not generate power when the sun is down or the wind isn’t blowing, storing their power for down times is the key to clean energy reliability.

The Form Energy battery is composed of cells filled with thousands of small iron pellets that, rust when exposed to air. When oxygen is removed the rust reverts to iron. By controlling the process the battery is charged and discharged.

The iron anode section of Form Energy's prototype iron-air battery. Courtesy Form Energy
The iron anode section of Form Energy’s prototype iron-air battery. Courtesy Form Energy

The plan is to mount small cells into larger modules, then assemble modules into batteries that can be scaled to power electric grids. Wiley expects to have a 300Mwh, full-scale pilot project, using 500 modules, up and running at the Great River Energy power plant in Minnesota in 2023.

In nearby Cambridge, researchers at Malta, Inc. are working on an energy storage technology based on an equally humble material: molten salt.

Electricity from the grid is converted into thermal energy and stored as heat in trays of molten sodium. When the grid needs energy the process is reversed and the molten sodium is used to generate electricity.

Biocompatible Thin Film: Heating Tissue with Surgical Precision to KILL CANCER


Human cells are vulnerable to intense heat and die rapidly above 42.5 °C. This property is utilized to treat cancer through a method called “thermotherapy” (also “hyperthermia”). The treatment has a long history, with even the ancient Greek physician Hippocrates being reported to use heat to eliminate cancer.

When tumor tissue is heated, the surrounding normal cells are also exposed to the heat. Although the blood vessels in normal tissue can dilate to release heat, the blood vessels in a tumor cannot, so only cancer cells reach a high temperature. It has also been reported that combining cancer thermotherapy (that works in this way) with radiation therapy and chemotherapy enhances the effect.

Although thermotherapy is promising as a cancer treatment, current methods require large devices for emitting radio waves or microwaves, so only a limited number of facilities are able to provide the treatment.

Applying polymeric thin film in medical treatment

Wearing a watch or other device on the body can cause skin irritation due to the mismatch in softness. Soft materials such as rubber can be used to avoid the mismatch, but this in turn leads to durability issues. To resolve this, Fujie Laboratory is developing a highly flexible polymeric thin film. Making the polymeric thin film thinner also makes it softer, allowing for the creation of flexible, comfortable devices (Advanced Functional Materials, “Flexible Induction Heater Based on the Polymeric Thin Film for Local Thermotherapy”).

Using an inkjet printer with conductive ink to draw a circuit on the polymeric thin film, it is possible to create a device that emits light and energy locally, with promising applications in medical treatment.

Local thermal device based on induction heating

The prototype was made based on the concept that when a polymeric thin film is attached to tumor tissue in vivo, and an alternating magnetic field is applied from outside the body, the thin film generates heat by the same principle as an induction cooktop.

Since the polymeric thin film is placed in vivo, the team decided to make it with biocompatible polylactic acid and use gold nano ink for inkjet printing. The gold nano ink needed to be heated to 250 °C to remove the stabilizer and induce conductivity. So it was printed on polyimide film made of a polymeric material that can withstand high temperature treatment.

After treatment at 250 °C, it was transferred to a polylactic acid thin film. The thickness of the thin film is only 7 µm, but it has the strength and flexibility to withstand handling with forceps used in endoscopic surgery.

The research team attached the device to the surface of an animal’s liver and applied a magnetic field. One minute of electricity raised the surface temperature by about 7 °C, and 5 minutes raised the temperature by about 8 °C. The liver used in the experiment was normal tissue, and a pathological examination afterwards revealed no burns or other damage.

Future prospects — Development of biocompatible medical devices

The polymeric thin film heating device can be sent non-invasively to tumor tissue using an endoscope. And by applying a magnetic field from outside the body, it is possible to heat the tumor tissue without the need for large equipment. This could likely lead to cancer thermotherapy becoming more widespread.

CREATING AN INJECTABLE SWARM OF BRAIN READING NANO-SENSORS – POTENTIAL FOR DIAGNOSING NEUROLOGICAL DISORDERS & AS A POWERFUL BRAIN-COMPUTER INTERFACE – UC SANTA CRUZ


USING NANO-SENSORS TO DIAGNOSE NEUROLOGICAL DISORDERS & FOR POWERFUL BRAIN-COMPUTER INTERFACES.

A team of scientists has developed a new kind of biosensor that can be injected straight into the bloodstream, and will then travel to your brain, where they will — according to the scientists behind the project — monitor your neural activity and even potentially thoughts.

The cell-sized nanosensors, aptly named NeuroSWARM3, can cross the blood-brain barrier to the brain, where they convert neural activity into electrical signals, allowing them to be read and interpreted by machinery, according to work by a team of University of California, Santa Cruz scientists that will be presented next week at a virtual Optical Society conference.

The tech could, the researchers say, help grant extra mobility to people with disabilities in addition to helping scientists understand human thoughtbetter than before. However, they haven’t yet been tested on humans or even animals.

“NeuroSWARM3 can convert the signals that accompany thoughts to remotely measurable signals for high precision brain-machine interfacing,” lead study author A. Ali Yanik said in a press release. “It will enable people suffering from physical disabilities to effectively interact with the external world and control wearable exoskeleton technology to overcome limitations of the body. It could also pick up early signatures of neural diseases.”

It’s also a notably different approach to the problem of brain-computer interfaces from most high profile attempts, including Elon Musk’s Neuralink, which are working on implant-based solutions instead of nanosensor swarms.

During tests, the team found that their nanosensor swarm is sensitive enough to pick up on the activity of individual brain cells. Single-neuron readings aren’t new, but the ability to detect them with free-floating sensors, and especially the ability to wirelessly broadcast them through a patient’s thick skull, is an impressive technological development. If further tests continue to pan out, those capabilities could make real-time neuroscientific research simpler and neurological medicine more sophisticated.

“We are just at the beginning stages of this novel technology, but I think we have a good foundation to build on,” Yanik added. “Our next goal is to start experiments in animals.”

Mystery Solved? The hidden culprit killing lithium-metal batteries from the inside – Sandia National Laboratories


In this new, false-color image of a lithium-metal test battery produced by Sandia National Laboratories, high-rate charging and recharging red lithium metal greatly distorts the green separator, creating tan reaction byproducts, to the surprise of scientists. Credit: Katie Jungjohann

For decades, scientists have tried to make reliable lithium-metal batteries. These high-performance storage cells hold 50% more energy than their prolific, lithium-ion cousins, but higher failure rates and safety problems like fires and explosions have crippled commercialization efforts. Researchers have hypothesized why the devices fail, but direct evidence has been sparse.

Now, the first nanoscale images ever taken inside intact, lithium-metal coin batteries (also called button cells or watch batteries) challenge prevailing theories and could help make future high-performance batteries, such as for electric vehicles, safer, more powerful and longer lasting.

“We’re learning that we should be using separator materials tuned for lithium metal,” said battery scientist Katie Harrison, who leads Sandia National Laboratories’ team for improving the performance of lithium-metal batteries.

Sandia scientists, in collaboration with Thermo Fisher Scientific Inc., the University of Oregon and Lawrence Berkeley National Laboratory, published the images recently in ACS Energy Letters. The research was funded by Sandia’s Laboratory Directed Research and Development program and the Department of Energy.

Internal byproduct builds up, kills batteries

The team repeatedly charged and discharged lithium coin cells with the same high-intensity electric current that electric vehicles need to charge. Some cells went through a few cycles, while others went through more than a hundred cycles. Then, the cells were shipped to Thermo Fisher Scientific in Hillsboro, Oregon, for analysis.

When the team reviewed images of the batteries’ insides, they expected to find needle-shaped deposits of lithium spanning the battery. Most battery researchers think that a lithium spike forms after repetitive cycling and that it punches through a plastic separator between the anode and the cathode, forming a bridge that causes a short. But lithium is a soft metal, so scientists have not understood how it could get through the separator.

Harrison’s team found a surprising second culprit: a hard buildup formed as a byproduct of the battery’s internal chemical reactions. Every time the battery recharged, the byproduct, called solid electrolyte interphase, grew. Capping the lithium, it tore holes in the separator, creating openings for metal deposits to spread and form a short. Together, the lithium deposits and the byproduct were much more destructive than previously believed, acting less like a needle and more like a snowplow.

“The separator is completely shredded,” Harrison said, adding that this mechanism has only been observed under fast charging rates needed for electric vehicle technologies, but not slower charging rates.

As Sandia scientists think about how to modify separator materials, Harrison says that further research also will be needed to reduce the formation of byproducts.

Scientists pair lasers with cryogenics to take “cool” images

Determining cause-of-death for a coin battery is surprisingly difficult. The trouble comes from its stainless-steel casing. The metal shell limits what diagnostics, like X-rays, can see from the outside, while removing parts of the cell for analysis rips apart the battery’s layers and distorts whatever evidence might be inside.

“We have different tools that can study different components of a battery, but really we haven’t had a tool that can resolve everything in one image,” said Katie Jungjohann, a Sandia nanoscale imaging scientist at the Center for Integrated Technologies. The center is a user facility jointly operated by Sandia and Los Alamos national laboratories.

She and her collaborators used a microscope that has a laser to mill through a battery’s outer casing. They paired it with a sample holder that keeps the cell’s liquid electrolyte frozen at temperatures between minus 148 and minus 184 degrees Fahrenheit (minus 100 and minus 120 degrees Celsius, respectively). The laser creates an opening just large enough for a narrow electron beam to enter and bounce back onto a detector, delivering a high-resolution image of the battery’s internal cross section with enough detail to distinguish the different materials.

The original demonstration instrument, which was the only such tool in the United States at the time, was built and still resides at a Thermo Fisher Scientific laboratory in Oregon. An updated duplicate now resides at Sandia. The tool will be used broadly across Sandia to help solve many materials and failure-analysis problems.

“This is what battery researchers have always wanted to see,” Jungjohann said.

More information: Katherine L. Jungjohann et al, Cryogenic Laser Ablation Reveals Short-Circuit Mechanism in Lithium Metal Batteries, ACS Energy Letters (2021). DOI: 10.1021/acsenergylett.1c00509

Provided by Sandia National Laboratories

A high-energy density and long-life initial-anode-free lithium battery


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Cathode and electrolyte design strategies for the researchers’ anode-free Li cell system. Credit: Qiao et al.

Lithium-metal batteries (LMBs), an emerging type of rechargeable lithium-based batteries made of solid-state metal instead of lithium-ions, are among the most promising high-energy-density rechargeable battery technologies. Although they have some advantageous characteristics, these batteries have several limitations, including a poor energy density and safety-related issues.

In recent years, researchers have tried to overcome these limitations by introducing an alternative, anode-free lithium battery cell design. This anode-free design could help to increase the  density and safety of .

Researchers at the National Institute of Advanced Industrial Science and Technology recently carried out a study aimed at increasing the energy density of anode-free lithium batteries. Their paper, published in Nature Energy, introduces a new high-energy-density and long-life anode-free lithium battery based on the use of a Li2O sacrificial agent.

Anode-free full-cell battery architectures are typically based on a fully lithiated cathode with a bare anode copper current collector. Remarkably, both the gravimetric and volumetric energy densities of anode-free lithium batteries can be extended to their maximum limit. Anode-free cell architectures have several other advantages over more conventional LMB designs, including a lower cost, greater safety and simpler cell assembly procedures.

To unlock the full potential of anode-free LMBs, researchers should first figure out how to achieve the reversibility/stability of Li-metal plating. While many have tried to solve this problem by engineering and selecting more favorable electrolytes, most of these efforts have so far been unsuccessful.

Others have also explored the potential of using salts or additives that could improve the Li-metal plating/stripping reversibility. After reviewing these previous attempts, the researchers at the National Institute of Advanced Industrial Science and Technology proposed the use of Li2O as a sacrificial agent, which is pre-loaded onto a LiNi0.8Co0.1Mn0.1O2 surface.

“It is challenging to realize high Li reversibility, especially considering the limited Li reservoir (typically zero lithium excess) in the cell configuration,” the researchers wrote in their paper. “In this study we have introduced Li2O as a preloaded sacrificial agent on a LiNi0.8Co0.1Mn0.1O2 cathode, providing an additional Li source to offset the irreversible loss of Li during long-term cycling in an initial-anode-free cell.”

In addition to employing Li2O as a sacrificial agent, the researchers proposed the use of a fluoropropyl ether additive to neutralize nucleophilic O2-, which is released during the oxidation of Li2O, and prevent the additional evolution of gaseous O2 resulting from the fabrication of a LiF-based electrolyte coated on the surface of the battery’s cathode.

“We show that O2– species, released through Li2O oxidation, are synergistically neutralized by a fluorinated ether additive,” the researchers explained in their paper. “This leads to the construction of a LiF-based layer at the cathode/electrolyte interface, which passivates the cathode surface and restrains the detrimental oxidative decomposition of ether solvents.”

Based on the design they devised, Yu Qiao and the rest of the team at the National Institute of Advanced Industrial Science and Technology were able to realize a long-life 2.46 Ah initial-anode-free pouch cell. This cell exhibited a gravimetric  of 320 Wh kg-1, maintaining an 80% capacity after 300 operation cycles.

In the future, the anode-free lithium battery introduced by this research group could help to overcome some of the commonly reported limitations of LMBs. In addition, its design could inspire the creation of safer lithium-based rechargeable batteries with higher energy densities and longer lifetimes.


Explore further

An anode-free zinc battery that could someday store renewable energyMore information: A high-energy-density and long-life initial-anode-free lithium battery enabled by a Li2O sacrificial agent. Nature Energy(2021). DOI: 10.1038/s41560-021-00839-0.

Journal information: Nature Energy