Posted By Graphene Council, Friday, June 26, 2020
Overwhelming European demand sees Australia’s battery anode company Talga Resources plan for expanded output at its new Swedish battery anode factory.
Expressions of interest received for Talga’s lithium-ion battery anode products exceed 300% of planned annual capacity of the Vittangi Anode Project, the company says.
Talnode products are now in 36 active commercial engagements covering the majority of planned European li-ion battery manufacturers and six major global automotive OEMs.
Talga says it’s expanding the scale of the Niska scoping study for the Vittangi Project to review larger anode production options as a result of this significant interest.
Li-ion battery megafactories are set to require more than 2.5 million tonnes per annum (tpa) active anode material by 2029, up from about 450,000 tpa anode production today, with Europe the fastest growing market.
That’s because worldwide li-ion battery demand continues to rapidly increase, with global battery manufacturing capacity set to exceed 2.5 tera-Watt hours (TWh) per annum by 2029 across 142 battery plants.
“Our engagement with European battery companies and automotive OEMs has grown rapidly, with customers attracted by the potential of locally produced anode at competitive costs and with world-leading sustainability,” Talga managing director Mark Thompson says.
”As we progress Talnode-C through commercial qualification stages with customers it is pleasing to note that interest now greatly exceeds our original planned production, and that the need to review expansion options has arisen this early.”
The increased interest means the company is targeting completion of the Niska scoping study in Q3 2020.
While COVID-19 has severely impacted EV sales in the short term, Bloomberg New Energy Finance data shows EV sales hold up better than internal combustion engine (ICE) vehicles due to new (lower cost) models and supportive government policies.
In the quarters prior to the COVID-19 outbreak, EV sales as a percentage of total passenger vehicles rose rapidly in the EU, with Germany and France recording increases of 100% during the period.
Numerous countries across Europe have implemented some form of financial incentives towards customer uptake of EVs, and post COVID-19 these have increased markedly in some countries.
Talga is entering the European market at a time when 100% of anode supply is still sourced from Asia. The company’s marketing team reports that, post COVID-19, localisation is becoming an increasingly significant factor influencing customer’s purchasing decisions.
Researchers at Swinburne University of Technology’s Centre for Translational Atomaterials have developed a highly efficient solar absorbing film that absorbs sunlight with minimal heat loss and rapidly heats up to 83°C in an open environment.
The graphene metamaterial film has great potential for use in solar thermal energy harvesting and conversion, thermophotovoltaics (directly converting heat to electricity), solar seawater desalination, wastewater treatment, light emitters and photodetectors.
The researchers have developed a prototype to demonstrate the photo-thermal performance and thermal stability of the film. They have also proposed a scalable and low-cost manufacturing strategy to produce this graphene metamaterial film for practical applications.
“In our previous work, we demonstrated a 90 nm graphene metamaterial heat-absorbing film,” says Professor Baohua Jia, founding Director of the Centre for Translational Atomaterials.
“In this new work, we reduced the film thickness to 30 nm and improved the performance by minimising heat loss. This work forms an exciting pillar in our atomaterial research.”
Lead author Dr. Keng-Te Lin says: “Our cost-effective and scalable structured graphene metamaterial selective absorber is promising for energy harvesting and conversion applications. Using our film an impressive solar to vapour efficiency of 96.2 percent can be achieved, which is very competitive for clean water generation using renewable energy source.”
Co-author Dr. Han Lin adds: “In addition to the long lifetime of the proposed graphene metamaterial, the solar-thermal performance is very stable under working conditions, making it attractive for industrial use. The 30 nm thickness significantly reduced the amount of the graphene materials, thus saving the costs, making it accessible for real-life applications.”
Electrons can behave like a viscous liquid as they travel through a conducting material, producing a spatial pattern that resembles water flowing through a pipe. So say researchers in Israel and the UK who have succeeded in imaging this hydrodynamic flow pattern for the first time using a novel scanning probe technique. The result will aid developers of future electronic devices, especially those based on 2D materials like graphene in which electron hydrodynamics is important.
We are all familiar with the distinctive patterns formed by water flowing in a river or stream. When the water encounters an obstacle – such as the river bank or a boat – the patterns change. The same should hold true for electron flow in a solid if the interactions between electrons are strong. This rarely occurs under normal conditions, however, since electrons tend to collide with defects and impurities in the material they travel through, rather than with each other.
Making electrons hydrodynamic
Conversely, if a material is made very clean and cooled to low temperatures, it follows that electrons should travel across it unperturbed until they collide with its edges and walls. The resulting ballistic transport allows electrons to flow with a uniform current distribution because they move at the same rate near the walls as at the centre of the material.
If the temperature of this material is then increased, the electrons can begin to interact. In principle, they will then scatter off each other more frequently than they collide with the walls. In this highly interacting, hydrodynamic regime, the electrons should flow faster near the centre of a channel and slower near its walls – the same way that water behaves when it flows through a pipe.
Extremely clean 2D materials
In recent years, researchers have created extremely clean samples from 2D materials such as graphene to act as testbeds for studying electron hydrodynamics. The vast majority of this work, however, involved measuring electron transport, which only probes the physics of electrons at fixed positions along the perimeter of the device.
“Hydrodynamics, on the other hand, brings to mind dynamic images of electrons swirling around with interesting spatial patterns,” says Joseph Sulpizio, who is one of the lead authors of this new study. “Such patterns have been predicted in theory but never imaged spatially.”
Poiseuille current profile
Sulpizio and the other researchers, led Shahal Ilani at Israel’s Weizmann Institute for Science in collaboration with Andre Geim’s group at Manchester University, have now imaged the most fundamental spatial pattern of hydrodynamic electron flow for the first time. They obtained this parabolic or Poiseuille current profile by studying electrons travelling through a conducting graphene channel sandwiched between two hexagonal boron nitride layers equipped with electrical contacts.
Under an applied electric field, the electrons produce a voltage gradient along the current flow direction. Unfortunately, this local voltage gradient is the same for both hydrodynamic and ballistic electron flow and so cannot be used to distinguish between the two regimes. Ilani and colleagues overcame this problem by applying a weak magnetic field to the sample, which produces another voltage – the Hall voltage – perpendicular to the direction of the current. The gradient of this voltage is very different for hydrodynamic and ballistic flow.
The researchers imaged the Hall voltage profile for both flow regimes using a scanning probe recently developed in their laboratory. This ultraclean carbon nanotube single-electron-transistor-based device is held at cryogenic temperatures and is extremely sensitive to local electrostatic fields. The current flowing through it is thus indicative of the local potential of the sample and voltage gradients associated with the Hall voltage.
By measuring this current, the team was also able to observe the transition between the regime in which electron-electron scattering dominates and that in which the electrons flow ballistically. “As expected, we observed a flat Hall field profile across the graphene channels at low temperatures,” Sulpizio tells Physics World. “Upon heating, however, the profile becomes strongly parabolic, revealing less current flow near the walls and more near the centre, which indicates the transition to hydrodynamic/Poiseuille flow.”
Magic-angle graphene reveals a host of new states
Implications for device development
The implications of the work, which has been published in Nature, are many, he says. Electron hydrodynamics only emerges at elevated temperatures (in contrast to many other kinds of electronic phenomena that exist only at very low temperatures) and this will be relevant for technological devices like computer chips that operate at room temperature. It will also be relevant in 2D van der Waals heterostructures like those made from graphene, and especially when they are super-clean. This behaviour is likely to play an important role in new generations of devices made from these materials.
“Looking further ahead, it might even be possible one day to engineer fundamentally new kinds of electronic devices that directly exploit electron hydrodynamics,” Sulpizio says. “When electrons interact hydrodynamically, their viscosity results in highly non-local spatial flow patterns that might be technologically advantageous.”
A toothpaste-like composite with hexagonal boron nitride developed by researchers at Rice University is an effective electrolyte and separator in lithium-ion batteries intended for high-temperature applications in a number of industries, including aerospace and oil and gas. (Source: Jeff Fitlow/Rice University)
One major and dangerous problem with lithium-ion batteries is that they can catch fire when heated to high temperatures, an issue that has caused damage and even death when devices ignited without warning.
Now researchers at Rice University have come up with a solution to this very serious safety problem in the form of a combined electrolyte and separator for rechargeable lithium-ion batteries that supplies energy at usable voltages and in high temperatures. The material is a toothpaste-like composite that is capable of performing well at and withstanding high temperatures without combusting.
The problem with most current lithium-battery chemistries is that they present safety concerns when heated beyond 50C (122F) due to the electrolyte/separator combination used in them, explained Marco-Tulio Rodrigues, a Rice graduate student and one of the authors of a paper on the research published in Advanced Materials Science.
The work of the Rice team addresses both the issue of developing a separator that will not cause a short circuit and an electrolyte that doesn’t have the tendency to catch fire, he said.
The batteries made with the components they developed functioned as intended in temperatures of 50C (122F) for more than a month without losing efficiency, according to researchers. Moreover, test batteries consistently operated from room temperature to 150C (302F), setting one of the widest temperature ranges ever reported for such devices, they said.
To solve the electrolyte problem, researchers used solutions based on ionic liquids in the electrolytes, which have largely been proposed as substitutes for organic solvents in the electrolyte of lithium-ion batteries because they present a much higher thermal stability, Rodrigues explained.
“These chemicals are basically special salts with a very low melting point, in such a way that they are liquid at room temperatures,” he said. “They are completely nonflammable and they do not evaporate at all until they decompose, which occurs beyond 350C (662F).”
With the electrolyte situation solved, researchers turned their attention to finding a new separator, which they addressed with a material called hexagonal boron nitride, also known as white graphene.
Samsung phones will have super fast graphene, rather than lithium, batteries within the next two years.
According to leaker Evan Blass, Samsung is developing graphene batteries for its smartphones — and we could see the first ones arrive as soon as next year.
The reason for the change is clear: exceptionally fast charging. Reportedly a full charge will now take just half an hour on a graphene battery, and despite recent leaps forward in fast-charging that would still be a significant improvement on the standard lithium ion battery.
The news is the latest update we’ve heard since Samsung reported in 2017 that they had developed a graphene ball that could charge 5x faster than standard phone batteries (reported by Cnet). So why is it taking so long for the batteries to make it onto the market? Blass surmises that’s it’s simply a question of economics: “they still need to raise capacities while lowering costs.” Once that balance is found, this tech innovation could be a true game changer.
This news comes shortly after the release of Samsung’s latest flagship phablet, the Galaxy Note 10. It boasts an impressive 3500mAh battery, while it’s big brother — the Galaxy Note 10 Plus — has a whopping capacity of 4300mAh. But they’re not just about batteries. While both run on the powerful Exynos 9825 chip, specifications diverge significantly. The Galaxy note 10 has an 6.3-inch 1080 x 2280 resolution screen, with 8GB of RAM and a triple camera set-up; meanwhile, the Galaxy Note 10 Plus has an even larger 6.8-inch screen with a sharper 1440 x 3040 resolution, 12GB of RAM, and its triple rear camera is complemented with a Time of Flight 3D sensor.
With all the recent innovations in smartphone batteries, from huge capacities to Qi wireless charging, you might have thought there was nowhere else to innovate. But graphene technology could point towards an era of even faster charging. All that’s left to be seen is how pricey is it, and whether the capacity will be enough to satisfy demanding users.
|Researchers in China have demonstrated a graphene nanocomposite foam-based water harvesting system to harvest water from air. The team reports their findings in ACS Applied Materials & Interfaces (“Superelastic Graphene Nanocomposite for High Cycle-Stability Water Capture-Release under Sunlight”).|
|Only 30% of all freshwater on the planet is not locked up in ice caps or glaciers (not for much longer, though). Of that, some 20% is in areas too remote for humans to access and of the remaining 80% about three-quarters comes at the wrong time and place – in monsoons and floods – and is not always captured for use by people. The remainder is less than 0.08 of 1% of the total water on the planet (read more: “Nanotechnology and water treatment“)|
|An abundance of water equivalent to about 10% of the total freshwater in lakes exists in the earth atmosphere, which can be a non-negligible freshwater resource to fight against the water shortage.|
|That’s where the graphene nanocomposite foam comes in: The foam realizes water harvesting through a capture-release cycle:|
|1) the capture process is composed of moisture adsorption from air by lithium chloride (LiCl) and water preservation by poly(vinyl alcohol) (PVA) and|
|2) the release relies on the solar-to-thermal transformer, reduced graphene oxide (rGO), to facilitate evaporation. In addition, polyimide is employed as a substrate material for the purpose of 3D porous structure formation and mechanical property enhancement.
Photograph, schematic diagram, and SEM images of the graphene nanocomposite foam. (a) Photograph of the graphene nanocomposite foam. (b) Schematic diagram of the graphene nanocomposite foam. Foam was prepared through a three-step process: freeze-drying, thermal annealing, and hydrophilic treatment. rGO/PI nanosheet, as the basic unit, can achieve the water harvesting capture-release cycle without additional energy input. (c) SEM image presents a porous structure of the rGO/PI foam without hydrophilic treatment. (d) Magnified SEM image of the rGO/PI foam without hydrophilic treatment to show a relatively smooth surface of the nanosheet. (e) SEM image of the graphene nanocomposite foam after hydrophilic treatment. (f) Magnified SEM image of the hydrophilic rGO/PI foam with bumped nanostructures. (g) Schematic diagram of the water vapor capture-release cycle.
LiCl and PVA were responsible for the water capture and water storage, respectively. Adsorbed water was stored as crystallized water in LiCl hydrates and the free water molecules were restrained by hydroxyl groups on PVA through the hydrogen bond, which led to the transformation of the nanosheet from dry status to wet status. Opposite procedure, from wet status to dry status, was realized by the rGO converting the solar energy to thermal energy to facilitate water evaporation under irradiation. (Reprinted with permission by American Chemical Society) (click on image to enlarge)
|The as-fabricated foam can adsorb water up to 2.87 g per gram in 24 hours at a relative humidity of 90% and a temperature of 30°C, and release almost all the uptake water when it is exposed under a flux of 1 sun (1000 W per square meter, equal to the light intensity of natural sunlight) for 3 hours.|
|At the same time, the functional foam shows superelasticity, lightweight, and remarkable reusability, thus revealing its possibility to practical use.|
|The researchers write that, even though the rGO/PI nanocomposite foam can harvest freshwater from air, it is essential to enhance water harvesting efficiency.|
|“Another big challenge impedes the water harvesting system utilization to explore a more cost-effective way to prepare the products,” they conclude. “Though the three-step synthesis method and the composition of the foam have been optimized, it is still necessary to reduce the cost and increase the fabrication efficiency. Meanwhile, environmentally friendly materials are recommended, which would take the water harvesting system one step further to commercial application and large-scale production.”|
|By Michael Berger – Nanowerk|
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