Graphene Aluminum Ultra Fast Charging Batteries
Tesla and GM are not the only ones with promising battery technologies. The GMG (Graphene Manufacturing Group) are developing an aluminum-ion (al-ion) battery made from graphene, a form of graphite. These batteries have the potential for ultra fast charging capabilities that outperform lithium-ion (li-ion) batteries. Think about fully charging a depleted battery to 100% in 1 to 5 minutes. That is about 10X more than lithium-ion charging while also lasting longer with less cooling requirements.
The GMG has partnered with the Australian Institute for Bioengineering and Nanotechnology at the University of Queensland (AUS) to conduct experiments. What they discovered is the performance of graphene aluminum-ion is much better overall than lithium-ion batteries. It is also much more efficient, so that would be a key benefit to users.
What Is Graphene?
Graphene is a thin layer made from carbon, which has a hexagonal arrangement of the carbon atoms. This has the atoms arranged in a honeycomb lattice configuration. At the nano level, graphene exhibits certain properties that make it a good application for conducting electricity and absorbing thermal energy.
Graphene has a high electrical conductivity feature, which makes it an excellent conductor of electrons. Its electrical current density would be a million times that of copper (CU). The electrical conductivity of copper (10.E6 Siemens/m) is 58.7 MS/m. That would put graphene at up to 100 MSM/m. Yet graphene is less dense as a material than copper. It is only 2.26 g/cm³ while copper is 8.95 g/cm³.
Graphene, as a material, is also an excellent heat conductor. In theory, graphene could absorb an unlimited amount of heat. It contradicts the law of thermal conduction (Fourier’s Law) at the micrometer scale. According to tests with graphene, researchers discovered that the larger the segment, the more heat it could transfer.
When charging batteries or energy storage devices, the power density gives an indication of how quickly a cell can charge and discharge. Lithium-ion batteries have a power density between 250–700 W/kg. An aluminum-ion battery is 7,000 W/kg. This puts the level of aluminum-ion with that of ultra capacitors which have a power density of 12,000–14,000 W/kg. Capacitors are electrical components that store a charge, which can then be distributed to provide power.
In an aluminum-ion battery the cathode consists of the graphene while the anode is made of aluminum, while the electrolyte is made of aluminum chloride. An aluminum-ion battery would be a type of hybrid supercapacitor. While supercapacitors are known for high capacitance, they have lower energy density. Aluminum has the type of properties needed for fast charge and quick discharge cycles. Pair that with graphene and you have higher energy density. That is not always the case though, so something had to be done about it.
The higher energy density was accomplished at the University of Queensland using a new process. This required drilling holes in the graphene platelets in order to allow the aluminum atoms to sit tighter, in order to reduce the weight needed to store a charge. The performance data gathered from the tests (using coin cells) show that the energy density of the aluminum-ion battery was between 150–160 Wh/kg. That shows that the energy density still falls short at the cell level compared to that of Tesla’s 2170 cells (2019) that have 247 Wh/kg.
Despite falling short to Tesla, the advantage the aluminum-ion cells have is that they do not overheat as much as lithium-ion cells. More energy can be put to use rather than wasted as heat. That means even at higher energy densities, heat can reduce efficiency by a certain amount. If more of the energy were utilized, then al-ion would require less cooling, while increasing performance.
The Challenges Ahead
The most anticipated application for batteries is for powering devices. Charge times are often long and if the user has no backup battery, they are just going to have to wait. Higher energy density batteries with faster charging times are going to be a game changer in that regard, every time this issue comes up. The question is will al-ion batteries be up for that challenge.
As the world moves from gas to EV (Electric Vehicles), a robust charging infrastructure needs to be in place. EV should be charged safely without frying the electric power grid. It requires plenty of power to charge EV. Tesla supercharging stations can pump out up to 250 kW of electricity at a rate of 15 minutes for 60 kWh. To charge 10X faster, you would need to provide 2.5 MW of power.
The issue here is more about whether chargers are capable of meeting capacity as more EV hit the road. You now need faster charging in order to accommodate the demand. If users have to wait 1 hour for charging, that does not have a good look on the EV industry. If you have 100 EV charging at the same time at the same station, that would require a massive amount of energy supplied.
This becomes more about a problem of scaling, rather than technology. The battery can be made, but if you don’t have a reliable infrastructure in place, it won’t be useful. Even being able to manufacture the batteries is not going to be the problem, it will be whether GMG or other manufacturers can do at scale. The costs of selling the battery are also another thing that users would need to know. Will the batteries be expensive is the question, since producing graphene is not exactly a simple and cheap process.
Al-ion batteries are still a prototype in mid-2021, not a commercial product like Tesla’s li-ion batteries. These batteries are also not yet used in any actual application other than for research.
The materials are abundant and relatively inexpensive. They can also be recycled easier so they provide a more environmentally friendly solution as a greener technology.
The key benefits that can be gained are mainly:
- Greener alternative to li-ion batteries
- Much more efficient in heat conduction
- Faster charging times
This can have a wide range of applications, from automobiles to smartphones. A longer lasting charge can be the difference for many consumers. It can be the type of game changer that can affect several industries. The thing to remember is that there is an amount of lag between test to production. Many things need to be ironed out before any product can hit the market. For al-ion batteries it could still be a long time before there is any available.
What remains to be seen is manufacturing the batteries at scale and meeting standards of safety for consumer use. The manufacturer must also have a customer who will use these batteries in their products. At the same time, other technologies could emerge that make current developments obsolete. The market usually decides which is better or best. In the end, the more energy efficient the battery the better it will be for everyone.