Starting from the Mercedes-Benz AVTR concept car, is there hope for graphene batteries?

The inventor of the car has always wanted to reinvent the car.

Mercedes-Benz unveiled a pure electric concept car AVTR using graphene batteries at this year's CES. However, this does not mean that graphene batteries can finally be mass-produced. Since the discovery of graphene materials several years ago, the power battery industry has been hoping to use this material to seek performance breakthroughs.

Mercedes-Benz has only provided a new idea, which is still a long way from practical application.

Let's first take a look at the graphene battery on the Mercedes-Benz AVTR. The automotive industry unanimously believes that this is a technological breakthrough achieved by Mercedes-Benz in power batteries, and graphene can finally shine in power batteries. However, Mercedes-Benz did not directly use the term "graphene battery". What it described on the AVTR was "a battery pack built with graphene-based organic battery chemical raw materials", which is a very rigorous expression. The main function of graphene is to replace metals and rare earths, and ultimately the entire battery can be completely organic and degradable. In other words, the key role of graphene in this power battery is not to improve performance.

 According to Mercedes-Benz, the AVTR concept car is equipped with a 110kWh battery pack, which can achieve a range of 700 kilometers. Compared with the current mainstream power batteries, such performance parameters do not seem to have much breakthrough. Taking the battery recently released by NIO as an example, the 100kWh battery pack can achieve a maximum range of 615 kilometers on the EC6, which is the level of an SUV. Considering the sports car shape and many dynamic design details of the Mercedes-Benz AVTR, it is not difficult for the 110kWh battery pack to achieve a range of more than 700 kilometers. However, Mercedes-Benz also mentioned that this battery can be fully charged in 15 minutes, which is precisely the greatest contribution of graphene in battery applications.

Mercedes-Benz did not explicitly use the term graphene battery, and even when introducing this graphene battery, it only emphasized "organic". So is the AVTR concept car the beginning of graphene batteries moving towards practical application? Will the vision of graphene making a big leap in power and electric performance fall through again?

The last time we were given hope was the graphene solid-state battery from the startup Fisker. According to the plan, the Fisker EMotion concept car will use graphene batteries, which is the main research and development direction of Fisker Nanotech, a joint venture established by Fisker and the startup Nanotech Energy Inc. in 2016. If all goes well, the graphene battery can allow the Fisker Emotion to achieve a maximum range of 643 kilometers and replenish nearly 200 kilometers of range in 9 minutes. Although it is nothing in terms of the development process in 2019, back in 2016, it was the graphene battery that gave us hope.

Later, graphene batteries were considered a scam, and one of the evidences was the collapse of the Fisker joint venture. Fisker turned to cooperate with LG to produce MCN batteries, which later became the choice of high-end electric vehicles. As for Fisker's other more mainstream pure electric SUV exhibited at CES this year under the name of Fisker Ocean, this is another story.

The 2010 Nobel Prize in Physics was awarded to two scientists who discovered graphene. When they successfully separated this versatile substance from graphite, it was considered the hope of batteries. Since then, the battery industry has never given up on the research and development of graphene batteries.

Graphene has the characteristics of high thermal conductivity and low resistance. When graphene becomes an anode embedded with lithium ions, it can exert excellent conductivity. As an active material of power batteries, it can increase the capacity of traditional lithium batteries by more than two times. If graphene can be successfully applied to power batteries, then the biggest drag of electric vehicles today - range and charging time - can be completely solved.

For example, in 2014, a Spanish graphene startup developed a graphene polymer battery that can provide a maximum range of 1,000 kilometers and only takes 8 minutes to charge, which is a level that cannot be achieved with the current development of ternary lithium battery cell technology and high-power charging.

As for the Mercedes-Benz AVTR concept car, it does not particularly emphasize related performance improvements, or does not reach the level that graphene batteries should have. It can be considered that the application of graphene in this new type of battery has not been clearly used to improve performance.

In fact, the application of graphene in batteries has been tried many times but has never been truly mass-produced and was even debunked. One important reason is that the actual effect is difficult to confirm and requires extremely high costs. Graphene is added to batteries, whether as a conductive agent or an active material. There is currently no clear data on the actual application in the industry, and it is more of a theoretical performance improvement. In terms of performance tips, there has been controversy in the battery industry since the Nobel Prize. The role of graphene in battery negative electrode materials is more to improve charging efficiency, but the effect on energy density is not obvious. Even if graphene is used in supercapacitors instead of lithium batteries, the energy density will actually go backwards.

As for another more practical reason, the cost. A few years ago, the cost of graphene was calculated by gram, which was hundreds of times higher than the price of graphite, an important material in lithium batteries. If it was used in the battery of an electric car, the price of graphene alone would be too high for many products. And based on the price in 2018, the price of high-purity graphene is still as high as thousands of yuan, and the output and cost are far from being able to achieve large-scale commercial use.

Of course, the automotive industry is not the only one eyeing the "treasure" of graphene. The mobile phone industry also hopes to rely on graphene to break through the battery life. Not long ago, Huawei was "revealed" that the upcoming P40 will use graphene batteries, which can fully charge a 5000 mAh battery in 45 minutes, but this news was soon debunked. The reason is that graphene battery technology and commercialization are not mature, etc. In 2015, Huawei also released a battery fast charging technology that uses graphene to dissipate heat, which can charge a 3000 mAh battery by 48% in 5 minutes, but this has remained in the experimental stage for many years.

It seems that the graphene technology used in the Mercedes-Benz AVTR concept car is far from being a real "graphene battery". But apart from the voices about whether graphene batteries are a scam, Mercedes-Benz has at least given another idea - organic and environmentally friendly.

Regardless of the feasibility of this battery being fully charged in 15 minutes and the supporting high-power charging solution, Mercedes-Benz mentioned that this battery uses graphene-based organic battery chemistry to replace the rare earth and metal materials currently used in conventional batteries on the market. Such an introduction is still very vague, and the role of graphene in it is not clearly introduced. The only thing that can be confirmed is that this expensive new battery is unlikely to see mass production in the short term.

However, it may be able to point out a way for the future of power batteries. After years of development, electric vehicles have reached the point where they need to be eliminated and recycled. The mainstream solution is to recycle the obsolete power batteries into cascade recycling and energy storage. For example, Japan is actively developing the recycling of electric vehicle batteries for household power supply.

Even if energy storage cannot be used, there are still a lot of recyclable metal materials after the power battery is disassembled, and they can even be used again in the battery industry after processing. Otherwise, improper handling of power batteries will cause great pollution and harm to the environment. However, the recycling and reuse of power batteries is a new industry that still needs subsidies.

The Mercedes-Benz AVTR concept car talks about the future. It claims that this new power battery can be completely degraded and is an organic battery. Does this mean that after it is reused in cascade recycling and energy storage, it can also be properly processed without any burden or extra cost? Is this the best destination for power batteries?

Combined with the use of a large number of organic chemical materials in this concept car, including the interior, Mercedes-Benz should be outlining an environmentally friendly automotive future for us. As for the long-discussed and ideal graphene battery, it has not yet arrived.

The inventor of the car not only wanted to reinvent the car, but also believed that he had a responsibility to make cars benefit mankind and the earth.