Category Archives: SGU

graphene aluminium ion batteries – the big breakthrough?

GMG's coin battery unveiled

GMG’s coin battery unveiled

So I’ve heard more exciting info recently from the Skeptics Guide to the Universe (SGU), this time returning me to Australia – Queensland more specifically. And some are describing this as the big battery technology breakthrough many of us have been waiting and hoping for.

So, lithium-ion batteries go back to the late sixties, though we can go back further to the twenties when it was noted that lithium’s electrochemical properties, such as low density, high specific capacity and low redox potential, would make it a likely battery anode material. I’m tempted to go into a thorough self-education investigation of how li-ion batteries were developed and how they work, but I’ll resist it and go straight to the new tech.

Graphene is an allotrope, or form, of carbon, as is diamond and various fullerenes. It consists of a single layer of atoms in a hexagonal lattice. Graphite, a very stable carbon allotrope, consists of stacked layers of graphene. The clean technology company Graphene Manufacturing Group (GMG), based in Queensland, manufactures graphene via a ‘proprietary production process’ which utilises natural gas (methane) rather than graphite. Its current principal focus, according to its website, is ‘developing applications for energy saving and energy storage solutions’. In its corporate overview, here’s what the company has to say on the battery front:

In the energy storage segment GMG and the University of Queensland are working collaboratively with financial support from the Australian Government to progress research and development, and ultimately explore the commercialization of GMG graphene aluminium-ion batteries. Aluminium-ion batteries have the potential to have better energy density than lithium-ion batteries. Graphene Aluminium-ion batteries may eliminate many disadvantages of LI Batteries, including the risk of overheating/fire and performance degradation. Management believes that successful commercialization of the Graphene Aluminium-ion batteries would result in a superior substitute to LI Batteries in targeted applications.

At this point they are promising longer battery life – up to 3 times – and very much faster charging – up to 60 times, something like a supercapacitor. There are no problems with overheating – lithium requires a cooling system, using more space and energy. They also describe the battery as ‘planet-friendly’, in that it doesn’t require scarce resources, such as lithium, which has become much more expensive recently. In fact, Australia is the world’s largest producer of bauxite ore, from which aluminium and gallium are extracted, so these batteries could put Australia in the box seat for production and manufacture. A ‘secure and simplified supply chain’ is one of the benefits touted by the company. Other benefits include safety (no catching fire), stability (no spontaneous discharge, i.e. energy leakage), and improved energy and power density. The batteries will have a longer lifespan, with many charge-discharge cycles. And at the end of the day they should be more recyclable. GMG also promises that these new batteries can be fitted within existing battery housing – no modifications required.

So how does the battery work? Here’s where I have to learn stuff. These are a class of rechargeable battery in which aluminium ions flow from the anode (the positive electrode) to the cathode and back. As to the cathode, I think that’s where graphene comes in. Based on breakthrough technology developed at the University of Queensland’s Australian Institute for Bioengineering and Nanotechnology, the battery cells ‘use nanotechnology to insert aluminium atoms inside tiny perforations in graphene planes’. Aluminium ions are trivalent, meaning they have three valent, or ‘free’, electrons to play with, compared to lithium’s one. This has had both benefits and disadvantages in the past. The three units of charge per ion means more energy density or storage capacity, but, according to Wikipedia, ‘the electrostatic intercalation of the host materials with a trivalent cation is too strong for well-defined electrochemical behaviour’. I don’t know what this means, but presumably this is the problem that the use of graphene solves.

Whether these new batteries will effectively replace li-ion batteries is a question. Established industries don’t move aside easily, and it’s likely that the new technology will be better for some applications than for others. Li-ion is not only well established, the technology is constantly improving. And nickel metal hydride, the previous form of rechargeable battery, still has its place, I believe.

Things are apparently moving fast. GMG CEO and Managing Director Craig Nicol said, “We are currently looking to bring coin cell commercial prototypes for customer testing in 6 months and a pouch pack commercial prototype – used in mobile phones, laptops etc. – for customer testing in 18 months. We are really excited about bringing this to market. We aim to have a viable graphene and coin cell battery production facility project after customer validation that we would likely build here in Australia”. According to the SGU the company expects to have EV batteries ready by 2024.

So that’s about it. But here’s some other random but relevant info:

Since 2005, lithium costs have increased nine-fold, while aluminium costs have increased by 20%.

Currently 90% of lithium is accessed from China, 10% from Chile – but I heard on Fully Charged that Australia is a major source of lithium, so I’m confused.

Basic ingredients of the new battery: ‘aluminum foil, aluminum chloride (the precursor to aluminium and it can be recycled), ionic liquid and urea’ (Craig Nicol)

From graphene-info.com: Now, GMG has shared the initial performance data when tested in coin cells for the patent-pending surface perforation of graphene in aluminium-ion batteries developed by the Company and the University of Queensland (“UQ”). Currently, GMG Graphene is producing coin cell prototypes for customer testing in Q4 2021.’

From Dr. Ashok Nanjundan, GMG’s Chief Scientific Officer: “This is a real game-changing technology which can offer a real alternative with an interchangeable battery technology for the existing lithium-ion batteries in almost every application with GMG’s Graphene and UQ’s patent-pending aluminium ion battery technology. The current nominal voltage of our batteries is 1.7 volts, and work is being carried out to increase the voltage to directly replace existing batteries and which lead to higher energy densities….. The real differentiator about these batteries is their very high power density of up to 7000 watts/kg, which endows them with a very high charge rate. Furthermore, graphene aluminium-ion batteries provide major benefits in terms of longer battery life (over 2000 charge / discharge cycles testing so far with no deterioration in performance), battery safety (very low fire potential) and lower environmental impact (more recyclable)”.

So, I’ll be following developments over the next few months and years…

References and links

https://www.graphene-info.com

https://www.forbes.com/sites/michaeltaylor/2021/05/13/ev-range-breakthrough-as-new-aluminum-ion-battery-charges-60-times-faster-than-lithium-ion/?sh=3be2b61a6d28

https://en.wikipedia.org/wiki/Aluminium-ion_battery

flying close to the sun

solar wind and our magnetic shield-field – so much more to learn

I’m not a physicist, or anything else scientific, I’m just an ageing sponge, trying to suck up knowledge and understandings in the diminishing time I have left. Physics is just one vast web of knowledge that I’ve barely stepped upon, to mix metaphors, but that won’t stop me trying to make some sense of orbital mechanics in this post, with the help of the Skeptics’ Guide to the Universe (episode 826), and other sources.

The NASA Parker Solar Probe (PSB) is the fastest human-built object, and also holds the record for closeness to the sun. It was launched in August 2018 and weighs around 73 kgs. Named for Eugene Parker – a multi-award-winning solar astrophysicist who worked out the effects of the solar wind and predicted the spiral shape of the solar magnetic field in the outer solar system – the PSB recently (only a month ago) got to within about ten million kilometres of the sun’s service. The next closest artificial object was the Helios spacecraft, in 1976, at a distance of about 43 million kms. Mercury, which has a highly elliptical orbit, only gets as close as 47 million kms at perihelion.

The PSB is part of NASA’s Living With a Star (LWS) program, which investigates the Sun-Earth system as it affects our sun-dependent and sometimes sun-threatened lives. For example, the SGU references the Carrington Event, the largest geomagnetic storm on record, caused by a solar coronal mass ejection hitting the Earth’s magnetosphere in early September 1859. If such an event occurred today, it would cause massive damage to our electrical grid systems and satellites. So the PSB is designed to study the sun’s corona and solar wind, presumably in the hope of providing an early warning of future events. For this purpose it’s loaded with various forms of detecting and measuring instruments. However, my interest here is in trying to understand how the probe gets from Earth to the Sun’s corona, how it’s expected to reach speeds of up to 690,000 km/h, and how it can withstand the temperatures in the corona.

It has apparently been calculated that it takes 55 times the energy to get to the Sun as it takes to get to Mars. This is all about orbital mechanics – the sun is spectacularly massive, making up 99.8% of the mass of the solar system. That means it also has a spectacularly massive gravitational pull on the Earth, and all other orbiting bodies. It’s the Earth’s ‘sideways’ velocity (107,208 km/h) that keeps it from falling into the sun. So the Earth’s orbital velocity needs to be taken into account – cancelled out – in planning a trip to the Sun. It turns out that it’s inordinately difficult to do so. With current technology they have only managed to cancel out about 80% of this velocity – which will bring the PSB close to the Sun but not close enough. Travelling to the outer planets is much easier. The probe would leave Earth at 40,000 km/h (escape velocity) and would require a relatively slight boost (6-7,000 km/h) to reach Mars, and further small boosts to reach the other outer planets.

The solution to this cancellation problem is to employ an orbital manipulation called Venus Earth Gravity Assist (VEGA). The PSB was sent to Venus to reduce the sideways orbital motion. Every swing around Venus further reduces this motion, and allows the PSB to decrease the orbital perihelion ultimately to about 7 million kms, at which time it will be travelling at its maximum speed. This will occur at Christmas Eve 2024 (they can be quite precise, apparently), after the last of its planned seven swings around Venus. The probe’s orbit around the Sun will be highly elliptical, with a minimum of time spent around perihelion, to prevent radiation damage to the craft and instrumentation. 

Of course the PSB will also come equipped with probably the most sophisticated heat shield or thermal protection system ever built, which will protect it not only from the intense heat and radiation but from high-velocity dust particles. It measures about 2.5 metres in diameter and is made from carbon foam between layers of superheated carbon-carbon composite, aka reinforced carbon-carbon (carbon fibre in a matrix of graphite). Its outer aluminium oxide coating is, naturally, reflective white, to protect probe and equipment from a maximum temperature at perihelion of about 1370 degrees celsius. NASA expects that the inner side of the shield will be at a little under 30 degrees – so cool in fact that some instruments will be independently heated to operate at maximum efficiency. The probe has been created to be as autonomous as possible, given its distance from Earth. For example, if instrumentation somehow becomes exposed to radiation, four light sensors will ‘detect the first traces of direct sunlight coming from the shield limits and [engage] movements from reaction wheels to reposition the spacecraft within the shadow again’, to quote the Wikipedia article on the probe. 

This solar probe concept was first mooted in the late 1950s but was regularly postponed due to costs. The initial idea was for a less direct route using a gravity assist from Jupiter, which would have created a longer and more expensive mission and would have required a nuclear battery called a radioisotope thermal generator. Something to research in another post maybe. 

So I won’t pretend that I understand all the mathematics of this probe’s voyage, but I do know that it has been successful so far, at least in terms of its travel – the Venus assists and the solar orbits, which will all come to an end on August 29 2025. As to whether it will be successful in its research tasks, that will have to be evaluated over time. What precisely are those research tasks? There are three main ones: to trace the flow of energy that heats the corona and accelerates the solar wind, to determine the structure and dynamics of the magnetic fields that create the solar wind, and to determine what mechanisms accelerate and transport energetic particles.

Whether the knowledge gained will protect us from future solar wind and electromagnetic activity nobody knows. Predictions about the future are probably the most uncertain predictions of all. 

References

Episode #826

https://science.nasa.gov/heliophysics/programs/living-with-a-star

https://en.wikipedia.org/wiki/Parker_Solar_Probe

https://www.cosmos.esa.int/documents/1700208/1718748/06+Luhmann+Living+with+the+Sun.pdf/337d8891-ba5f-6534-42ea-92eff2131797

https://en.wikipedia.org/wiki/Carrington_Event

https://www.nasa.gov/feature/goddard/2018/its-surprisingly-hard-to-go-to-the-sun