Lithium News

Is there an alternative to nanostructuring electrode materials to speed up ionic diffusion in lithium-ion batteries and so increase their maximum power output and charging rates? Yes, according researchers at the University of Cambridge in the UK, who have shown that two complex niobium tungsten oxides can intercalate large amounts of lithium even when the oxides are microns in size. The new work will be important for developing systems that require high power delivery and/or fast charging (think of a mobile phone that could be fully charged in just minutes). It could also have implications for solid-state energy storage for example, in electric cars, and grid-scale storage for solar power.

Ubiquitous in portable electronics, rechargeable lithium-ion batteries consist of two electrodes – anode and cathode – separated by an electrolyte. When the battery is being charged with electrical energy, lithium ions move from the cathode through the electrolyte to the anode, where they are absorbed and stored into the bulk of the anode material.

The maximum power output and the rate at which these batteries can be charged and discharged is typically limited by solid-state ionic transport in the electrodes. To speed up ionic diffusion and so reach high power and rapid charging, the size of the active particles in the electrodes is often reduced to the nanoscale – so that the lithium ions have a shorter distance to travel. Nanoparticles are difficult to pack together, however, which affects the battery’s volumetric energy density. They are also difficult to process and can undergo unwanted chemical reactions with the electrolyte, so ultimately reducing battery life and increasing cost.

“Nanoscaling and nanostructuring are simply not needed”

A team of researchers led by Clare Grey has now found that two complex “block” or “bronze-like” niobium tungsten oxides (Nb16W5O55 and Nb18W16O93) can intercalate large quantities of lithium at high rates even when the particles are as big as 30 microns in size. Measurements of how lithium ions move through the materials (using a technique called pulse field gradient NMR) point to room-temperature diffusion rates that are several orders of magnitude higher than those in typical electrode materials such as Li4Ti5O12 and LiMn2O4. This rapid solid-state lithium transport in the bulk materials leads to extremely high volumetric capacities and rate performance so nanoscaling and nanostructuring are simply not needed, says study lead author Kent Griffith.

Most conventional negative electrodes in lithium-ion batteries are made of graphite, which has a high energy density, explains Grey. However, when charged at high rates, spindly lithium fibres known as dendrites form. These can create a short circuit and cause the batteries to catch fire, or even explode.

“In high-rate applications, safety is a bigger concern than under any other operating circumstances,” she says. “These materials and potentially others like them, would definitely be worth looking at for fast-charging applications where you need a safer alternative to graphite.”

“One of the most important aspects of our work is the discovery that energy storage material candidates with unconventional structures can boast exceptional performance,” Griffith tells Physics World. “This means that complex, relatively unexplored regions of composition/structure phase space may hold promise for next-generation devices. In particular, breaking away from the often-held belief that nanoscaling is mandatory to achieving to high-rate storage may help the transition from new materials to applications.”

Higher densities at high discharge/charge rates
One of the reported niobium tungsten oxides is built from 4 x 5 blocks of (Nb,W)O6 octahedra that are connected along shear planes, he adds. The other, the “bronze-like” phase, is held open by pillars of oxygen that prop open the atomic layers. Both compounds are easily synthesized and allow lithium ions to quickly move through them in 3D. Their architectures also make them more rigid than other battery materials.

“They may be able to safely offer higher densities at high discharge/charge rates and could thus be used in systems requiring high power delivery and/or fast charging, possibly in combination with lower rate, high-energy-density batteries,” he says. The fact that they can readily be produced without any additional chemicals or solvents is another point in their favour.

The team, which includes researchers from the Advanced Photon Source at the Argonne National laboratory in the US and the Diamond Light Source in Didcot in the UK, says that it is now busy conducting further electrochemical tests on niobium tungsten oxides and optimizing them for specific applications. “We will also be applying the design principles and advanced characterization techniques employed in this work to unearth new material compositions and chemistries,” says Griffith.

When it comes to new materials, thin is most definitely in. Brazilian researchers have created a new two-dimensional material called hematene, which is made up of sheets of iron ore just three atoms thick. And as is often the case with 2D materials, hematene seems to have different properties to its regular form.

The most famous 2D material is undoubtedly graphene, a slimmed-down form of carbon that’s extremely strong, lightweight, and electrically and thermally conductive. But it’s far from alone in that dimension – recently, scientists have also created 2D sheets of black phosphorus, gallium, molybdenum disulfide and chromium triiodide, all boasting a wide range of unusual properties.

The newest member of the family, hematene, comes from hematite, a naturally-occurring mineral that provides our main industrial source of iron. By subjecting the ore to a process called liquid-phase exfoliation, the team created sheets just three iron and oxygen atoms thick.

The researchers then studied the properties of the material, to see how those of its 2D form differed from the regular 3D stuff. Hematene was found to be ferromagnetic, as opposed to the antiferromagnetic nature of hematite. It was also shown to have the potential to be a good photocatalyst, able to use sunlight to speed up chemical reactions.

Absorbing sunlight from the ultraviolet to the yellow-orange part of the spectrum, both hematite and hematene can be photocatalytic, but the former is too weak to tap into. Hematene, on the other hand, fared better, thanks to its thinness. When photons strike the material, the positive and negative charges that are generated don’t have far to travel to get to the surface. The researchers improved its performance by pairing hematene with arrays of titanium dioxide nanotubes.

“Hematene may be an efficient photocatalyst, especially for splitting water into hydrogen and oxygen, and could also serve as an ultrathin magnetic material for spintronic-based devices,” says Douglas Soares Galvão, an author of the study.

The team says that other iron oxides and related materials could also get the 2D treatment in future, leading to a whole range of new materials with strange properties.

Tesla and other proponents of virtual power plants and demand management schemes have scored a significant win after the country’s main energy market rule maker gave its support to the idea that they can compete freely on the wholesale electricity market.

The decision announced by the Australian Energy Market Commission on Thursday is likely to encourage new players in the market to aggregate solar and battery storage installed in homes and businesses, as well as load controls, in a major shift to the way demand and supply is managed.

It is also likely to encourage proponents of technologies that would manage the charging of electric vehicles, and the use of their combined battery capacity in the grid, and it could encourage peer-to-peer trading.

In short, it means that customers with battery storage and electric vehicles can strike contracts with providers other than their main retailers to provide power to the grid when needed. It sets a signal that the Australian grid is finally moving to embrace 21st century technologies.

That said, the AEMC – after years of deliberation and after initially rejecting the idea – has only given approval in principle. The idea still awaits a specific rule request that will likely repeat the battle between the proponents of new technologies, and those locked in the past.

Having such mechanisms will likely be a blow to the major incumbent generators, particularly those – like Snowy Hydro – who rely on the existence of peak pricing events and the subsequent demand for market caps to underwrite their power plants, and particularly the proposed Snowy 2.0 pumped hydro scheme.

The federal government-owned Snowy Hydro was one of the most vocal opponents of the proposal, saying such a move could “reduce short-term high spot prices” and arguing that this would not necessarily be in the “overall interest of consumers.”

The decision by the AEMC in its Reliability Frameworks Review shapes up a major victory for the likes to Tesla, sonnen, Simec Zen, Reposit, Redback, Sunverge, and others who have argued for the development of “virtual power plants”.

These are essentially rooftop solar and battery storage installations located “behind the meter” in homes and businesses which are connected by software. These “distributed energy resources” can be harnessed to help moderate prices and meet demand peaks.

Providers of demand response technologies, such as EnerNoc, who use load controls to reduce non-essential demand at certain times, have also supported the move.

The argument is that these technologies are cheaper, cleaner, smarter and faster than the current default response – which is to switch on dirty and expensive “peaking plants” powered by gas, diesel or even jet fuel.

Their case has been underlined by the performance of the Tesla big battery in South Australia, an early trial of Tesla’s proposed virtual power plant in Adelaide, and the success of other VPP trials and the big battery and demand response in the frequency and ancillary services market.

An example of how these projects can work is revealed in the US state of Vermont, where utility Green Mountain Power drew on electricity from 500 Tesla Powerwall batteries installed in about 400 homes to address peak demand.

The savings from wholesale electricity costs were so great – $US500,000 in one 1-hour peak demand period on July 5 – that GMP is able to offer the Powerwalls to consumers at just one-fifth of their normal price – $US1,500, or $15 a month – in exchange for being able to use some of the storage at certain times.

The companies operating in the Australian market, and some public interest groups, had fought for the same right to be recognised on equal footing with traditional fossil fuel generators, and to allow consumers to engage multiple retailers/aggregators at the same connection point.

“An active demand-side characterised by the active participation of consumers promotes efficient outcomes in the wholesale market,” the AEMC said in its concluding report.

Demand response has also been supported by the Australian Energy Market Operator, and particularly its CEO Audrey Zibelman, who has wanted to repeat the success of demand response in the US, where it accounts for up to 20 per cent of peak demand, in Australia.

However, the AEMC has rejected another key AEMO request – that of creating so-called “day ahead markets,” which it had argued was crucial to its ability to manage the grid and create price signals to the market. This proposal was also fought by incumbent generators.

The potential benefits for the AEMC ruling are summed up in this table above. But note the date when this was produced – in 2015. A year later, the AEMC declared it saw no barriers to demand management.

The change of heart has been a long time coming, and it’s not as though the likes of Tesla and others will be able to go out and offer these services tomorrow, as it still requires a specific rule change and more consideration.

The AEMC has said it is OK with the idea. But it notes that consumer advocacy groups the Total Environment Centre (TEC) and Public Interest Advocacy Centre (PIAC) have committed to presenting a rule change request soon. The devil will be in the detail of those proposals, and the response.

The AEMC notes that the increasing uptake of distributed energy resources, including solar PV, batteries, electric vehicles and dynamic controllable loads supports its decision.

“A formerly passive demand side is becoming increasingly engaged through the uptake of distributed energy resources which are greatly expanding the choices that consumers have to manage their energy needs at the household/business level,” it notes.

“(These resources) have the potential to provide value to consumers and NEM participants through the provision of wholesale services (such as FCAS) or network services (such as network congestion management).”

It notes the growing number of virtual power plants, where distributed energy resources are being orchestrated to provide services on a wholesale level.

These include Simply Energy’s virtual power plant, the AGL virtual power plant, and the South Australian Power Networks virtual power plant.

It noted that owners of EVs would be able to establish a separate retail relationship for their electric vehicle and maintain their existing retail relationship. “Implementing this arrangement would also allow for innovate approaches to retailing electric vehicle load to emerge,” it noted.

Note: The AEMC also released a report on frequency control, in which it recommends no immediate changes, but recognises there are some “existing inefficient regulatory barriers” that may hinder or prevent distributed energy resources from providing these services.

It makes recommendations, including proposed rule changes, on how these barriers could be addressed.

Toyota Motor Company is increasing its investment in hydrogen fuel cell vehicles (FCV). It is designing lower-cost, mass-market passenger cars and sport utility vehicles and even pushing the technology into trucks and buses to produce economies of scale.

Toyota wants to make FCV’s cheaper

Yoshikazu Tanaka, chief engineer of the Mirai said in an interview with Reuters: “We’re going to shift from limited production to mass production, reduce the amount of expensive materials like platinum used in FCV components, and make the system more compact and powerful.”

Many automakers and industry experts have mostly dismissed plans to expand the production of fuel cell vehicles (FCV) as being commercially unviable but Toyota hopes to prove them wrong. Toyota is busy cranking up improvements for its Miral hydrogen fuel cell vehicle expected to be released in the early 2020s. It has been around for some time as the appended photo shows.

Toyota planning new models of FCVs

The company also plans to introduce other models including SUVs, pick-up trucks, and commercial trucks beginning around 2025, a source with knowledge of the automaker’s plans said. However Toyota would not comment on its specific plans for the future. It has already developed prototypes of small delivery vans, and also large transport trucks.

Ikuo Ota, manager of the new business planning for fuel cell projects at Toyota said: “We are going to use as many parts from existing passenger cars and other models as possible in fuel cell trucks. Otherwise, we won’t see the benefits of mass production.”

Toyota expects improved performance from their FCVs

Toyota hopes to increase the driving range of its next Mirai model to 700-750 kilometers from its present approximately 500 kilometers. By 2025 it hopes to hit 1,000 kilometers far beyond present electric vehicle ranges.

Toyota continues to believe in potential of FCVs

Toyota has a strong belief that within the next 100 years hydrogen will become a key source of clean energy. The company has been busy developing FCVs since early in the 1990’s. Hydrogen is the most abundant element and it also has the advantage of storing more energy than a battery of equivalent weight.

Production of Mirai has been quite limited

Mirai was world’s first production FCV launched way back in 2014. However, it costs around $60,000 prior to any government incentives. There is an acute lack of refueling infrastructure. Less than six thousand have been sold around the world.

Forecasts see sale of FCV’s to make up only 0.2 percent of world passenger car sales by 2027 whereas battery EVs are expected to be 11.7 percent. However Toyota is reported to think that the demand for the vehicles will strengthen as countries strongly committed to EV’s such as China warm to the advantages of the technology. The company also sees the development of FCVs as a hedge against the possible scarcity of key EV battery materials such as cobalt.

For now the Mirai is hand-built in Toyota city producing only a few models a day. However, the company expects sales to rise to about 30,000 units annually after 2020 from about 3,000 now. To lower production costs the company will need to produce other models.

The company is also reducing other costs. Eri Ichikawa a fuel cell engineer said: “We’ve been able to decrease the platinum loading by 10 percent to 20 percent and deliver the same performance.”

Fuel Cell Vehicles

Wikipedia describes an FCV as follows: “A fuel cell vehicle (FCV) or fuel cell electric vehicle (FCEV) is a type of electric vehicle which uses a fuel cell, instead of a batt ery, or in combination with a battery or supercapacitor, to power its on-board electric motor. Fuel cells in vehicles generate electricity to power the motor, generally using oxygen from the air and compressed hydrogen. Most fuel cell vehicles are classified as zero-emissions vehicles that emit only water and heat. ”

Fuel cells are being developed and tested in trucks, buses, boats, motorcycles and bicycles, as well as other kinds of vehicles.

As of 2017 there is only limited infrastructure support for FCVs with only 36 hydrogen fueling stations available in the US. However, more are planned particularly in California. However there are stations in Japan, Europe and elsewhere with more being planned. However, some critics question whether the technology will ever be able to compete with other zero emission technologies.

A team of researchers from Denmark, Italy and Portugal recently discovered a new mechanism for controlling electronic devices using molecules. The researchers have shown that the ferroelectric ordering of polar molecules attached to the edge of graphene can be toggle-switched by an electrostatic gate and can be used for memory devices and sensors.

Molecular electronics aims to use individual molecules to control electronics. The large library of molecules and techniques to modify them can create more sophisticated electronics than previously thought possible. The normal hindrance is the small size of the molecules. It’s possible to create them, but they are incredibly difficult to handle. It is almost impossible to manipulate small enough features in ordinary materials to electrically connect with individual molecules.

The most common approach is the so-called mechanical break junction, which relies on creating “cracks” in wires small enough to bridge individual molecules. Obviously, this is not an easy task, especially because the molecules have many different ways to attach onto the wires at the atomic level. In nanoscale contacts even the smallest difference matters.

Jose Caridad from Technical University of Denmark came up with very a different approach: to use something that is already atomically small to trap the molecules: the 0.3 nm wide edge of graphene.

The researchers sandwiched graphene layers in hexagonal boron nitride crystals – which can play the role of an insulator. They carved square-shaped devices using common etching processes that cuts through the hBN-graphene-hBN sandwich and leaves the 1 atom thin graphene edge exposed.

While such devices are usually not particularly sensitive to the environment, the researchers found a way to make the graphene device react to water molecules in an unexpected way. The idea is to control the edge chemistry: the researchers attached different atoms to the graphene edges, before exposing them to water vapor and other polar molecules. With fluorine termination (which is common), the graphene nearly didn’t respond. Instead, with oxygen, the graphene device became much more sensitive to the presence of polar molecules.

A series of experiments showed that polar molecules can be aligned by a user-controlled electrical field in two positions (just like a toggle switch). This drastically changes the electron distribution in the graphene layer, and thereby the resistance and capacitance of the device. The key aspects of this behavior were successfully modeled and explained theoretically by atomistic and analytical calculations, led by Professor Mads Brandbyge at DTU Nanotech. The effect seems to be persistent: the aligned water molecules keep their orientation even when removing the field, creating exactly the type of hysteresis needed for novel memory devices.

Peter Bøggild, Professor at DTU Nanotech: “There are two important things we have learned. First: even for quite large devices – 5 µm in size – the behavior is completely controlled by a few molecules sitting along the edge. Using graphene edges to manipulate molecules is a fantastic way to trap molecules and explore new device functionalities. It also tells us that we have to careful; we are not always interested in devices changing their behavior in this way. We may think that we have protected the graphene, but if the edges are still exposed, all bets are off. Graphene is a nanomaterial where every atom counts – and the treatment of those delicate edges is absolutely crucial for any future electronics based on graphene”.

“We have a new platform for so-called memristive and memcapacitive devices – nanoscale devices that can be switched between different states and remember it,” says Jose Caridad, who initially discovered the effect and led the project, “This technology is important for internet of things and neuromorphic computing, and that’s where I want to go with it”.

Imagine if the US had these three things: access to unlimited electricity from clean sources everywhere in the country, an electricity grid impervious to outages and electricity prices that were even cheaper than they are today. These aspirations can become reality with advancements in energy storage.

This technology was developed right here in the good ole’ US of A, but unfortunately, the US is now falling behind other countries in this increasingly lucrative global market, and our outdated electric grid is growing more vulnerable to increasing threats like cyber-attacks and extreme weather. So how do we regain our leadership in this critical technology, and how can we increase the development and deployment of energy storage here at home? The answer is innovation.

What are the experts in the field saying?

Back in March, with the help of the Bipartisan House Advanced Energy Storage Caucus, UCS convened twenty-one experts on energy storage research, development and demonstration from around the country. The goal was to develop recommendations for congress on how the federal government could best support innovation in this game-changing technology. Our new policy brief, “Federal Support for Electricity Storage Solutions: State Perspectives on Research Development and Demonstration”, synthesizes the convening dialogue and includes a brief analysis of the applications and benefits of energy storage. It also identifies and prioritizes the most important research questions and breakthroughs needed to advance the technology. The brief highlights important ongoing work on energy storage across the federal government. And most importantly, it contains recommendations for policy-makers on how the federal government can best foster and support innovation in energy storage.

We wanted to hear diverse perspectives, so we included a broad cross section of technical experts from different states and regions, including university professors, start-ups, the national labs, small rural electric co-ops and big utility representation, conservative political voices, the defense community, former state and federal officials, and financial analysts.

Three important points of unanimous agreement at the outset of the convening: 1) Energy storage RD&D across the federal government is underfunded relative to the strategic importance of innovation in this technology. 2) “The U.S. is no longer the global leader in energy storage technology.” 3) The private sector is not making the needed investments in energy storage RD&D to achieve transformational change. Specific, strategic efforts are needed by the federal government to advance the technology.

The fiscal year 2019 “Minibus” is an opportunity

When congress returns from August recess, and the “minibus” conference committee resumes consideration of the fiscal year 2019 Energy and Water Appropriations bill, they can provide a big boost to our energy security and our economy by increasing our federal commitment to research, development and demonstration of energy storage. At present, we are only spending $41 million in fiscal year 2018 on the Department of Energy’s (DOE) flagship Energy Storage Program at the Office of Electricity (OE). We are not going to out-innovate China and South Korea with that kind of insufficient federal investment. For context, DOE is spending $1.2 billion in FY18 on nuclear energy RD&D.

The FY19 House bill surprisingly increases appropriations for OE’s energy storage program by $10 million, indeed a modest, but much needed increase, whereas the Senate bill keeps funding at FY18 levels. OE’s Energy Storage Program partners with industry, utilities, and state energy organizations to advance multiple storage technologies, improve performance, and reduce costs, and has a strong track record. This program focuses on research questions ranging from the applied early stage, to pre-commercialization and demonstration projects. Minibus conferees should support the House funding levels for this program.

Another important DOE program for energy storage RD&D is the Advanced Research Projects Agency -Energy (ARPA-E), which has invested between 10 and 15 percent of its funding in energy storage projects over the last several years. The Advanced Research Projects Agency—Energy (ARPA-E) pioneers transformational energy projects that represent high-risk but potentially game-changing technologies and provides effective technology-to-market advice to the best performers. For storage, ARPA-E takes this transformational approach to new chemistries, controller technologies, long-duration components, and cost reduction.

The FY19 House Energy and Water Appropriations bill cuts ARPA-E’s funding by 8 percent, but the Senate bill increases funding by 6%. Minibus conferees should take this opportunity to come together on this nonpartisan issue and do what’s best for the country by supporting the Senate funding levels for ARPA-E. The US must continue to innovate and lead in the energy technologies of the future.

We all want the US to be the country selling batteries instead of buying batteries in the 21st century. Increasing federal funding for energy storage research development and demonstration will pay big dividends for our economy and national security, while helping to make the US electricity grid cleaner, more reliable, and more affordable. We’re not doing enough; we’ve got to do more. Let’s hope congress seizes the opportunity in the FY19 budget.