The race for the next generation of Electric Vehicle (EV) batteries is on, and two of the biggest names in the tech industry have already picked sides.
The automotive industry is demanding new technologies to finally put an end to EV range limitation, as EVs are one of the few only products whose adoption is limited by battery performance. The customers’ range anxiety is real and batteries today are not sufficient to push the electrification shift. Only in the last several years have electric vehicles started to narrow the gap, but this is still not enough.
The two emerging battery chemistries to take EVs into the next era are lithium-ion based on Silicon anodes and lithium metal Solid State batteries. Two of the world's business titans are supporting each one of the two different technologies; Elon Musk and Tesla are betting on Silicon anodes while Bill Gates has recently heavily invested in a leading Solid State startup.
This is not the first time Elon Musk and Bill Gates have had some disagreements. That also happened when Bill Gates decided to buy a Porsche Taycan electric car and not Tesla, and Elon didn't really like it, to say the least.
This is becoming more of just a battery race. It’s the race for the future.
Photo by John Holden on Unsplash
Lithium-Ion Silicon Anode Batteries
The first type of technology involves adding a considerable amount of Silicon to the graphite based anodes of lithium batteries. The advantage of using Silicon in the battery anode is that it is a very energetic material (its specific capacity is up 10 times more than that of graphite) resulting in increased battery energy per weight and volume. In addition, replacing graphite with Silicon at scale might also reduce production costs, a crucial parameter for the automotive industry.
In most of the cases, companies that are developing Silicon based batteries are mixing Silicon with graphite (up to 30% Silicon ) to get more energy. An illustrative example of using Silicon mix is done by Silanano, which produces and utilizes their own Silicon powder for their battery production. Another approach is using 100% pure Silicon anode, generating even higher energy density, like Amprius approach.
While Silicon provides considerably higher energy, there is a significant drawback that has limited its adoption until now. The material undergoes volume expansion while charging and discharging, limiting battery life and performance. In general, Silicon is mechanically less stable, which leads to degradation issues that have to be solved before commercial adoption.
Despite those challenges, there are commercialized Silicon based batteries already being used in a few industries, including automotive, like Tesla that leads the silicon adoption for EVs.
Elon Musk may be one of the most ardent supporters of Silicon, having already claimed that he wants to integrate batteries with high Silicon content in Tesla’s cars. Tesla’s CEO believes that the automotive industry should allocate resources to improve safety, efficiency and production costs of the Silicon anodes, in order to bring this solution faster to market and at a cost effective price.
Tesla is not the only company supporting Silicon batteries, Daimler is considered to be one of the top automotive investors in this technology with a recent $170M investment in Silanano.
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Solid State Battery
While incorporating Silicon into lithium-ion anodes can greatly improve the performance, many battery experts believe that Solid-State batteries might be the true next-generation technology for EVs. Solid State batteries aim to replace the liquid or polymer gel electrolytes in today’s lithium-ion batteries with solid electrodes and electrolytes. The key however lies in replacing the graphite anode with lithium metal or completely eliminating the anode during battery assembly. This approach offers much higher energy density (lithium metal is more energetic than graphite), and is relatively inexpensive. One of the most important aspects of Solid State is the improved safety, due to use of a solid, non-flammable electrolyte. Also, the technology claims to have higher electrochemical stability and excellent fast charging capabilities.
Thanks to all of these improvements, Solid State technology is considered by many to be the holy grail of batteries. But the technology is still nascent and has a long way to full commercialization. The manufacturing process has to improve in order to present competitive costs, especially when the product offering is for the automotive industry with aim to achieve a cost under $100/KWh in the next few years. Other challenges include stabilisation of lithium metal by prevention of dendrites formation during battery charge, improvement in operation functionality at low temperatures, and manufacturability at large scale.
World's leading car manufacturers, like Toyota and VW are investing in promising startups within the Solid State sphere, such as Solid Power and Quantumscape. While giants as Panasonic (partnership with Toyota) and Samsung are also developing their own Solid State batteries.
Bill Gates is an unquestionable leader when it comes to sustainable future and green energy, and has established the $1B Breakthrough Energy Ventures fund to invest in technologies that will get the world closer to the net zero carbon emission goal. Through the Breakthrough, he recently invested in Quantumscape. Besides his investment, he is a public advocate for this technology as the future of EVs and battery industry, but not only. The microsoft founder is also investing in energy storage technologies, like Ambri’s Li liquid metal Battery, as batteries for energy storage will play a crucial role (along solar panels and wind turbines) in producing 100% clean energy, which expected to happen in the next decade.
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How Can Both Silicon And Solid State Benefit From 3D Architecture?
Adopting Smart 3D Electrodes architecture is beneficial for any battery chemistry, but for these two emerging chemistry batteries, it can be a game changer by solving their key challenges and limitations.
Cathode thickness is THE major factor for battery performance with both of these technologies. No matter how high the anode energy it must be matched by low energy cathodes. To do so some must fabricate thicker cathode electrodes. Today there is a practical limitation to how thick the cathodes can be made. However 3D electrodes can easily overcome this limitation.
Furthermore, for Silicon batteries, Smart 3D Electrodes can mitigate their greatest drawback: the swelling of the Silicon that reduces the lifecycle and safety of the battery. The 3D metal structure can handle and accommodate Silicon expansion within its metal framework (see gif below)
Silicon swelling simulation captured by Addionics 3D structure
It’s too early to say what technology will win this race, as each battery has its own advantages and disadvantages. Nonetheless, both will have a critical role to play in the future of EVs and batteries. Silicon is currently more mature, more cost effective, and probably is closer to commercialization. On the other hand, Solid State batteries seem to bring a bigger step change in performance and safety.
Automotive OEMs already understand that they need to play a major role in this revolution and invest many resources and funds to get better understanding of the battery technologies and even to start manufacturing batteries themselves. Tesla was the first one to do that, but other OEMs such as VW group are following the way.
Most excitingly, Addionics’ 3D electrode architecture are ideally suited for both technologies and will contribute significantly to the electrification revolution we are all witnessing today.
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