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Tesla CEO Elon Musk Details New 50% More Energy Dense Batteries For Long Range Airplanes

In a new interview with Tesla Owners Silicon Valley, Elon Musk discusses the steps needed to produce an advanced lithium ion battery with 50% more energy density. Musk also talks about the limitations of such batteries and their possible application for long-range aircraft.


Tesla’s stated company goal is “to advance the world’s transition to sustainable energy.” Currently, Tesla has already demonstrated electric vehicles, utilizing batteries, can compete and in most cases surpass the functionality of internal combustion vehicles.

Now all Tesla has to do is scale vehicle production and march us towards a clean energy future. That on its own is an incredible achievement however if we are to eliminate greenhouse gas emissions from transportation altogether, cars are far from being the only culprit.

Currently, if we break down carbon dioxide emissions by sector, transportation accounts for about 25% with the remaining 75% made up of electricity production, industry, agriculture, and other smaller sources.

And if we were to further break down CO2 emissions from transportation. 45% comes from passenger vehicles like cars and buses, 29% comes from trucks carrying freight, 12% from aircraft, 10% from shipping, and the remaining 3% from trains and pipelines.

Tesla with the Model S, 3, X, & Y is already addressing a big chunk of greenhouse gas sources. And once the Tesla Semi, Cybertruck, and robotaxi (which according to Musk should be cheaper per mile than a bus) rollout next year, Tesla will be able to address the majority of greenhouse gas emissions from transportation.

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However, to fully transition the transportation system, Tesla’s current product roadmap still leaves out air travel and shipping.

Musk has famously said all modes of transportation excluding rockets will eventually transition to electricity. Musk has also on multiple occasions flirted with the possibility of Tesla building electric planes.

According to Elon, the biggest hurdle holding back airplanes from going electric is the energy density of lithium ion batteries. Currently, the most energy-dense commercially viable cells are found in Tesla vehicles. And these have an energy density of around 260Wh/Kg.

However, Musk has previously stated in order for electric planes to be viable, they’ll need batteries with an energy density of 400Wh/Kg. This means around 50% improvement from the current state of the art.

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And now, in a new interview with Tesla Owners Silicon Valley, Elon Musk has given us some details on how to improve the energy density of current batteries, cost limitations that come with advanced lithium ion cells, and how they are better applicable for long range airplanes.

Musk first starts out by saying “the difficulty of getting to, as you get to high energy density lithium ion, you need to change the anode to silicon. You get a dramatic increase in energy density as you switch the anode to silicon.”

Then Musk goes on to detail the challenges of going to a silicon anode “the problem with silicon is that it expands and contracts a lot during charge and discharge so, in the expansion and contraction it wants to kind of crumble, like mud cracks – essentially that is one way to think about it.”

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Continuing Musk says…

“so the problem with a pure silicon anode is that it is very difficult to have it stay together when you charge and discharge so, one of the things you can do is to add silicon to the carbon anode.

Carbon has only very minor expansion and contraction so it is easy to maintain a carbon anode and have its structure be robust across many charge cycles. And you can throw a little bit of silicon there and the silicon can kind of expand and contract inside the carbon matrix.”

But, as you start adding more silicon it gets harder and harder to maintain the structure of the anode. So our highest energy density cells will use, I don’t know like, 90% carbon maybe 10% silicon or something like that – It’s a small percentage.”

Finally talking about how to produce a pure silicon anode Musk says “there are much higher energy density cells you can get where if you have very precise construction of the anode, a little bit like chemical vapor deposition, you sort of print it like a circuit board situation such that the expansion, it can expand and contract without cracking, then you can get 50% higher energy density than we have in our cars.”

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You can watch Musk’s full interview with Tesla Owners Silicon Valley in the video linked below.

A 50% percent improvement in energy density will be a huge leap in battery technology. And if you are wondering why Tesla isn’t doing a silicon anode with chemical vapor deposition, Musk says “that is still very expensive. It might be suitable for long-range aircraft but it will not be economically viable for cars. So it is basically that situation, it is the only thing holding back electric cars, it is range.”

Despite laying a technology roadmap to improving battery energy density by 50% and, showing how they could be used for electric aircraft, Musk still did not commit to Tesla building an electric plane.

Musk currently says he has too much on his plate to take on electric jets. However, as Tesla matures into a more stable company, the serial entrepreneur might just change his mind.

Currently, there is no sign Tesla is working on electric planes. However, we will be sure to keep you posted if anything changes. Until then, make sure to visit our site regularly for the latest updates.

So what do you think? Excited to see Elon Musk already has a roadmap to increasing battery energy density by 50%? Also, do you think Tesla should produce electric planes? Let me know your thoughts in the comments below.

Image: Screenshot from Elon Musk’s interview with Tesla Owners Silicon Valley

For more information check out: Elon Musk Confirms New Giga Press Coming In 2 Weeks Is For Tesla Cybertruck Body

Tinsae Aregay has been following Tesla and The evolution of the EV space on a daily basis for several years. He covers everything about Tesla from the cars to Elon Musk, the energy business, and autonomy. Follow Tinsae on Twitter at @TinsaeAregay for daily Tesla news.