What’s Next: Beyond the lithium-ion battery


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

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

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

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

 

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

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

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

Lithium magic

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

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

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

Seeking a solid electrolyte

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

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

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

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

Meanwhile, back at the electrode

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

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

Lith Sulfur Batts c5cs00410a-f2_hi-res

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

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

Introducing new materials

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

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

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

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

 

 

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NREL Update: How Fast Can You Pump Hydrogen For An EV? NREL, Mercedes and GM Plan To Find Out


Pumping hydrogen for fuel cell-powered EVs is a bit trickier than plugging into an electric recharging station.

The pressure in HFEV tanks can get up into the 10,000 psi range, so hoses, fittings, gauges, and other fuel station gear all has to perform well under such pressure.

Even so, the optimal speed for pumping hydrogen for an HFEV at a station is not yet well defined at the moment, given the need for continuing station tank resupply, and for the fresh generation of hydrogen used to fill the tanks.

To help determine the optimal operational flow and requirements for HFEV stations, the US National Renewable Energy Laboratory, in Golden, CO, in a partnership with Mercedes-Benz and General Motors, is testing hydrogen filling at the lab’s Hydrogen Infrastructure Testing and Research Facility (HITRF), according to a facility spokesperson.

“It’s a cradle to grave investigation,” said the NREL guide who recently led a tour of the facility where new carbon fiber-reinforced tanks were on display.

The HITRF integrates commercial and test equipment in a system to mimic a hydrogen station, and it is the only facility in the national lab complex capable of fueling to the SAE J2601 standard — a fast-fueling protocol that dispenses 70 megapascals (MPa) of hydrogen at -40°C to the vehicle with a 3–5 minute fueling time, NREL’s program description says. A megapascal is about 145 psi. The SAE standard is “Fueling Protocols for Light Duty Gaseous Hydrogen Surface Vehicles.”

NREL and its partners are experimenting at the HITRF to help reduce the cost and installation time for a new hydrogen fueling station, to improve the stations’ availability and reliability, and to ensure the success of future hydrogen infrastructure deployment. One accident would attract far too much press attention.

The HITRF, with 340 kg of hydrogen storage on site, is the first facility of its kind in Colorado and serves as a proving ground for current generation component, system, and control testing, as well as perform testing for next-generation technology and controls.

NREL is also tapping federal funding for the HITRF, and helping US Department of Energy to test the hydrogen station equipment performance, or HySTEP devices as part of the US Department of Energy’s H2FIRST project.

The cost of each commercial hydrogen filling station could be high. One indicator of cost is that the Japanese government has invested $378 million to develop hydrogen infrastructure, of which about $1 million will be spent on each hydrogen station, according to a recent market analysis by Frost & Sullivan. “The cost of implementing a variable hydrogen pressure nozzle fuel station for storage and generation…has been the primary choking point in infrastructure expansion,” they say.

Other companies and entities involved in HFEV station development partnerships include the Hydrogen Energy Association, Seven-Eleven Japan Co. Ltd, HyFIVE, Linde, the California Fuel Cell Partnership, Ballard, and UK H2 Mobility, the analysts say.

The market for HFEVs, or fuel cell EVs, as they refer to them, is bright according to the analysts, who say about two million fuel cell vehicles are expected to be on the roads globally by 2030.

“The global market for FCEVs is estimated to reach about 583,360 units (per year) by 2030, with Asia Pacific (APAC) countries such as Japan and South Korea dominating the market with 218,651 and 80,440 units, respectively. FCEV markets in Europe and North America are projected to reach 117,000 units and 118,847 units, respectively, by 2030,” they say.

DOE targets having about 500,000 fuel cell cars on the road by 2030, Frost & Sullivan says.

Apart from its support of HFEV station development, DOE is supporting research that is working to reduce the price of an 80 kW fuel cell stack system to as little as $30. Along with reductions in the price of fuel cell stacks, efforts are also ongoing to lower the cost of hydrogen production to less than $2/kg, using the proton exchange membrane (PEM) electrolysis method, the analysts point out.

Over the next decade, an estimated $10 billion will be invested globally in developing hydrogen technology and infrastructure by a group of private investor companies in conjunction with Toyota, Daimler and BMW, Frost & Sullivan reckon.

The Californian government has approved an expenditure of $20 million annually on hydrogen station deployments with private companies, which had already invested over $20 million at the end of 2017, the analysts say.

NREL’s collaboration with Purdue University’s School of Mechanical Engineering has yielded new insights for lithium-ion (Li-ion) battery electrodes at the microstructural level, which can lead to improvements in electric vehicle (EV) battery performance and lifespan.


NREL LI Batt 1 2018018-thsc-micromodelElectrochemical simulation within a 3D nickel manganese cobalt electrode microstructure during a 20-minute fast charge. Streamlines represent Li-ion current in the electrolyte phase as ions travel through pores between the solid active material particles. Colors represent current magnitude. Illustration by Francois Usseglio-Viretta and Nicholas Brunhart-Lupo, NREL.

NREL’s collaboration with Purdue University’s School of Mechanical Engineering has yielded new insights for lithium-ion (Li-ion) battery electrodes at the microstructural level, which can lead to improvements in electric vehicle (EV) battery performance and lifespan. A stochastic algorithm developed by Purdue University, as part of NREL’s Advanced Computer-Aided Battery Engineering Consortium, is prominently displayed on the cover of the 10th anniversary issue of American Chemical Society’s Applied Materials and Interfaces. The NREL/Purdue team’s corresponding article, “Secondary-Phase Stochastics in Lithium-Ion Battery Electrodes” detailing the research and resulting discoveries, is showcased inside.

This work builds on earlier phases of the U.S. Department of Energy’s Computer-Aided Engineering for Electric-Drive Vehicle Batteries (CAEBAT) program. NREL’s energy storage team has led key research projects since CAEBAT’s inception in 2010, resulting in the creation of software tools for cell and battery design, as well as advancements in crash simulations used by many automakers.

This next phase of CAEBAT focuses on Li-ion electrode microstructure applications (accurately simulating the physics and geometric complexity of a battery) to better understand the impact materials and manufacturing controls have on cell performance. Li-ion batteries represent a complex non-linear system and considering EVs use larger batteries with more complex configurations, it is imperative to understand the interplay between electrochemical, thermal, and mechanical physics.

Says Kandler Smith, NREL co-author on the article, “Batteries are an exceedingly complex system—both in terms of their physics and geometry. In a real battery, it’s difficult to get a clear view of what’s going on inside, because so few measurements are possible. Models are a place where all physics can come together and the advantage of the model is that everything can be measured and probed. As we build an increasingly accurate physical understanding of batteries, we can expect that technological advances will follow.”

The secondary phase in Li-ion electrodes, comprised of inert binder and electrical conductive additives, has been found to critically influence various forms of microstructural resistances. This phase has benefits for improved electronic conductivity and mechanical integrity but may block access to electrochemical active sites and introduce additional transport resistances in the pore (electrolyte) phase, thus, canceling out its original advantages.

Because the secondary phase is important for electrode mechanical integrity and electronic conductivity, its recipe and morphology will have a strong impact on battery kinetics and transport. The algorithm created and explained in the journal article explores morphologies for this phase. Stochastics comes into play as each microstructure variant is numerically generated multiple times using random seeds to ensure statistically relevant conclusions. By simulating battery electrochemistry on the various microstructure geometries, researchers can calculate the pore size of an electrode’s microstructure geometry as well as the lithium displacement within an electrode to evaluate the difficulty of movement. Finding ways to overcome resistances via electrode microstructural modifications can greatly improve overall Li-ion battery performance.

The value of this work is that improvements to Li-ion batteries—the most expensive and complex component in EVs—is helping to overcome the concerns consumers have that limit EV adoption, including restricted driving range and high costs.

Rice U: New Lithium metal battery prototype boasts 3X the capacity of current lithium-ions ~ Dendrite Problem Solved?


graphene-nanotube-lithium-battery-4

Could a new material involving a carbon nanotube and graphene hybrid put an end to the dendrite problem in lithium batteries? (Credit: Tour Group/Rice University)

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.”

Rice logo_rice3So 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

 

The Coming Battery Revolution: Graphene and Batteries 



Graphene 2017 ImageForArticle_4454(1)Graphene and Batteries 

** Re-Posted from earlier article from Graphene Info

Graphene , a sheet of carbon atoms bound together in a honeycomb lattice pattern, is hugely recognized as a “wonder material” due to the myriad of astonishing attributes it holds. It is a potent conductor of electrical and thermal energy, extremely lightweight chemically inert, and flexible with a large surface area. It is also considered eco-friendly and sustainable, with unlimited possibilities for numerous applications.

In the field of batteries, conventional battery electrode materials (and prospective ones) are significantly improved when enhanced with graphene. Graphene can make batteries that are light, durable and suitable for high capacity energy storage, as well as shorten charging times.

It will extend the battery’s life-time, which is negatively linked to the amount of carbon that is coated on the material or added to electrodes to achieve conductivity, and graphene adds conductivity without requiring the amounts of carbon that are used in conventional batteries.

Graphene can improve such battery attributes as energy density and form in various ways. Li-ion batteries can be enhanced by introducing graphene to the battery’s anode and capitalizing on the material’s conductivity and large surface area traits to achieve morphological optimization and performance.

It has also been discovered that creating hybrid materials can also be useful for achieving battery enhancement. A hybrid of Vanadium Oxide (VO2) and graphene, for example, can be used on Li-ion cathodes and grant quick charge and discharge as well as large charge cycle durability.

In this case, VO2 offers high energy capacity but poor electrical conductivity, which can be solved by using graphene as a sort of a structural “backbone” on which to attach VO2 – creating a hybrid material that has both heightened capacity and excellent conductivity.

Another example is LFP ( Lithium Iron Phosphate) batteries, that is a kind of rechargeable Li-ion battery. It has a lower energy density than other Li-ion batteries but a higher power density (an indicator of of the rate at which energy can be supplied by the battery).

Enhancing LFP cathodes with graphene allowed the batteries to be lightweight, charge much faster than Li-ion batteries and have a greater capacity than conventional LFP batteries.

 

In addition to revolutionizing the battery market, combined use of graphene batteries and supercapacitors could yield amazing results, like the noted concept of improving the electric car’s driving range and efficiency.

Battery Basics

Batteries serve as a mobile source of power, allowing electricity-operated devices to work without being directly plugged into an outlet.
While many types of batteries exist, the basic concept by which they function remains similar: one or more electrochemical cells convert stored chemical energy into electrical energy. A battery is usually made of a metal or plastic casing, containing a positive terminal (an anode), a negative terminal (a cathode) and electrolytes that allow ions to move between them.

A separator (a permeable polymeric membrane) creates a barrier between the anode and cathode to prevent electrical short circuits while also allowing the transport of ionic charge carriers that are needed to close the circuit during the passage of current.

Finally, a collector is used to conduct the charge outside the battery, through the connected device.



Eneloop battery design

When the circuit between the two terminals is completed, the battery produces electricity through a series of reactions. The anode experiences an oxidation reaction in which two or more ions from the electrolyte combine with the anode to produce a compound, releasing electrons. At the same time, the cathode goes through a reduction reaction in which the cathode substance, ions and free electrons combine into compounds. Simply put, the anode reaction produces electrons while the reaction in the cathode absorbs them and from that process electricity is produced.

The battery will continue to produce electricity until electrodes run out of necessary substance for creation of reactions.

Battery types and characteristics

Batteries are divided into two main types: primary and secondary. Primary batteries (disposable), are used once and rendered useless as the electrode materials in them irreversibly change during charging. Common examples are the zinc-carbon battery as well as the alkaline battery used in toys, flashlights and a multitude of portable devices.

Secondary batteries (rechargeable), can be discharged and recharged multiple times as the original composition of the electrodes is able to regain functionality. Examples include lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics.

Batteries come in various shapes and sizes for countless different purposes. Different kinds of batteries display varied advantages and disadvantages.


Nickel-Cadmium (NiCd)
batteries are relatively low in energy density and are used where long life, high discharge rate and economical price are key. They can be found in video cameras and power tools, among other uses. NiCd batteries contain toxic metals and are environmentally unfriendly.


Nickel-Metal hydride
batteries have a higher energy density than NiCd ones, but also a shorter cycle-life. Applications include mobile phones and laptops.


Lead-Acid
batteries are heavy and play an important role in large power applications, where weight is not of the essence but economic price is. They are prevalent in uses like hospital equipment and emergency lighting.

Lithium-Ion (Li-ion) batteries are used where high-energy and minimal weight are important, but the technology is fragile and a protection circuit is required to assure safety. Applications include cell phones and various kinds of computers.


Lithium Ion Polymer (Li-ion polymer)
batteries are mostly found in mobile phones. They are lightweight and enjoy a slimmer form than that of Li-ion batteries.
They are also usually safer and have longer lives. However, they seem to be less prevalent since Li-ion batteries are cheaper to manufacture and have higher energy density.

Batteries and supercapacitors

While there are certain types of batteries that are able to store a large amount of energy, they are very large, heavy and release energy slowly.

Capacitors, on the other hand, are able to charge and discharge quickly but hold much less energy than a battery.

The use of graphene in this area, though, presents exciting new possibilities for energy storage, with high charge and discharge rates and even economical affordability.
Graphene-improved performance thereby blurs the conventional line of distinction between supercapacitors and batteries.

Li-Polymer battery vs Supercapacitor structure


Commercial Graphene-enhanced battery products

Graphene-based batteries have exciting potential and while they are not commercially available yet, R&D is intensive and will hopefully yield results in the future.

In November 2016, Huawei unveiled a new graphene-enhanced Li-Ion battery that can remain functional at higher temperature (60° degrees as opposed to the existing 50° limit) and offers a longer operation time – double than what can be achieved with previous batteries.

To achieve this breakthrough, Huawei incorporated several new technologies – including an anti-decomposition additives in the electrolyte, chemically stabilized single crystal cathodes – and graphene to facilitate heat dissipation. Huawei says that the graphene reduces the battery’s operating temperature by 5 degrees.



In June 2014, US based Vorbeck Materials
announced the Vor-Power strap, a lightweight flexible power source that can be attached to any existing bag strap to enable a mobile charging station (via 2 USB and one micro USB ports). the product weighs 450 grams, provides 7,200 mAh and is probably the world’s first graphene-enhanced battery.

In May 2014, American company Angstron Materials rolled out several new graphene products. The products, said to become available roughly around the end of 2014, include a line of graphene-enhanced anode materials for Lithium-ion batteries. The battery materials were named “NANO GCA” and are supposed to result in a high capacity anode, capable of supporting hundreds of charge/discharge cycles by combining high capacity silicon with mechanically reinforcing and conductive graphene.

Developments are also made in the field of graphene batteries for electric vehicles. Henrik Fisker, who announced its new EV project that will sport a graphene-enhanced battery, unveiled in November 2016 what is hoped to be a competitor to Tesla. Called EMotion, the electric sports car will reportedly achieve a 161 mph (259 kmh) top speed and a 400-mile electric range.

Graphene Nanochem and Sync R&D’s October 2014
plan to co-develop graphene-enhanced Li-ion batteries for electric buses, under the Electric Bus 1 Malaysia program, is another example.

In August 2014, Tesla suggested the development of a “new battery technology” that will almost double the capacity for their Model S electric car. It is unofficial but reasonable to assume graphene involvement in this battery.

UK based Perpetuus Carbon Group and OXIS Energy agreed in June 2014 to co-develop graphene-based electrodes for Lithium-Sulphur batteries, which will offer improved energy density and possibly enable electric cars to drive a much longer distance on a single battery charge.

Another interesting venture, announced in September 2014 by US based Graphene 3D Labs, regards plans to print 3D graphene batteries. These graphene-based batteries can potentially outperform current commercial batteries as well as be tailored to various shapes and sizes.

Other prominent companies which declared intentions to develop and commercialize graphene-enhanced battery products are: Grafoid, SiNode together with AZ Electronic Materials, XG Sciences, Graphene Batteries together with CVD Equipment and CalBattery.

Fisker-EMotion-TwitterRead More: The Fisker EV Sedan “EMotion”

EV Maker Fisker and Tesla Rival Plans to Use Graphene in Batteries to Extend Range – Improve Consumer Experience

MIT: Exiting Stealth Mode, 24M Takes On the Battery Industry: Will This be the Technology that Revolutionize Lithium Batteries?


Ion Lith 24M 062215 untitledA startup from one of the A123 founders aims to overhaul the making of lithium-ion batteries–but it’s not the first to try.

Aiming to completely overhaul the lithium-ion battery industry, MIT-based scientist Yet-Ming Chiang on Monday publicly unveiled his latest startup, called 24M.

The company uses a novel battery composition based on a semi-solid material that eliminates much of the bulk of conventional lithium-ion batteries—which are typically made up mostly of inactive, non-energy-storing materials—while dramatically increasing the energy density. Chiang and 24M CEO Throop Wilder also say that they can reduce the time needed to make a battery by 80 percent and the cost by 30 to 50 percent.

After five years of research and development, 24M has raised $50 million in funding from Charles River Ventures, North Bridge Venture Partners, and its strategic partners, along with a $4.5 million grant from the U.S. Department of Energy. It has strategic partnerships with the Japanese heavy-industry giant IHI and from PTT, the formerly state-owned Thai oil and gas company, which is increasingly moving into alternative energy.

Ion Lith II 24M 062215 images

Since a 2011 paper in the journal Advanced Energy Materials previewed 24M’s technology, the company has received a large amount of press coverage for a stealth-mode startup, including articles in this publication as well as a long, adulatory profile on the website Quartz. The company calls its new battery “the most significant advancement in lithium-ion technology since its debut more than 20 years ago.”

That would be a remarkable accomplishment, with the potential to drive the electric-vehicle market to a new level and accelerate the spread of renewable energy. But 24M faces a challenge that many previous companies with promising technology have failed to solve: how to revolutionize a manufacturing industry with huge amounts of capital sunk into extensive existing capacity.

Yet-Ming Chiang is personally familiar with this quandary: he was one of the founders of A123, the lithium-ion startup that received nearly a quarter of a million dollars in funding from the U.S. government, went public in the largest IPO of 2009, and filed for bankruptcy in 2012. A123 was done in by an EV market that grew slower than expected and by its close relationship with EV maker Fisker, which itself failed in 2013 and was purchased by the Chinese auto parts company Wanxiang Group. But it also stumbled in trying to compete with more established battery makers such as LG and Panasonic.

Chiang acknowledges the dilemma: “In the last decade, there have been a lot of new lithium-ion plants built, and the EV market has not materialized to fill these factories.”

Now, energy storage demand is soaring—for vehicles, for power grids, and for residences with distributed renewable generation, such as rooftop solar arrays. Capacity in the United States is expected to more than triple this year, and rapid growth will continue through the end of the decade, according to GTM Research.

That means that demand for a less expensive, more efficient technology should be robust. But the building boom of the previous decade means there’s also excess manufacturing capacity available to supply that market. LG Chem’s plant in Holland, Michigan, which makes batteries for the Chevrolet Volt and the Cadillac ELR, currently operates at about 30 percent of capacity, according to CEO Prabhakar Patil.

And established players are already increasing their output. Mercedes-Benz parent company Daimler, for instance, announced late last year it will invest 100 million euros ($113 million) to expand its lithium-ion manufacturing capacity through its subsidiary Deutsche ACCUmotive.

Then there’s the Gigafactory. Tesla’s giant Nevada plant will produce 35 gigawatt-hours’ worth of batteries a year, dwarfing any previous manufacturing ventures for lithium-ion batteries.

Meanwhile, improvements in the manufacturing of conventional lithium-ion batteries are reducing the cost per kilowatt-hour of existing systems—even as research into next-generation chemistries, such as lithium-sulfur and lithium-air, continues at institutions around the world.

In short, 24M is attempting to transform a worldwide manufacturing industry in which established players with deep pockets are investing hundreds of millions in the expansion of existing processes. That’s a tough road even for a startup with a novel and exciting technology.

Chiang and CEO Wilder are undeterred. “This is the next great mega-market,” says Wilder. “To quote Elon Musk, the world is going to need multiple gigafactories.”

Graphene Quantum Dots Coated VO2 Arrays for Highly Durable Electrodes for Li and Na Ion Batteries: The Next Generation of ‘Post-Lithium’ Batteries?


Nano Coatings Batteries nl-2014-04038s_0006Abstract

Nanoscale surface engineering is playing important role in enhancing the performance of battery electrode. VO2 (Vanadium Oxides) is one of high-capacity but less-stable materials and has been used mostly in the form of powders for Li-ion battery cathode with mediocre performance.

In this work, we design a new type of binder-free cathode by bottom-up growth of biface VO2 arrays directly on a graphene network for both high-performance Li-ion and Na-ion battery cathodes. More importantly, graphene quantum dots (GQDs) are coated onto the VO2 surfaces as a highly efficient surface “sensitizer” and protection to further boost the electrochemical properties. The integrated electrodes deliver a Na storage capacity of 306 mAh/g at 100 mA/g, and a capacity of more than 110 mAh/g after 1500 cycles at 18 A/g. Our result on Na-ion battery may pave the way to next generation postlithium batteries.

Link to paper: http://pubs.acs.org/doi/abs/10.1021/nl504038s

Source: ACS Nano

School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore

School of Materials Science and Engineering and §Energy Research Institute @ NTU Nanyang Technological University, Singapore 639798, Singapore
College of Optical and Electronic Technology, China Jiliang University, Hangzhou 310038, China