The Era of "Supercharged" Batteries Is Approaching
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The Era of “Supercharged” Batteries Is Approaching

by | published February 14th, 2020

As veteran readers of Oil and Energy Investor well know, before careers in intelligence, academe, and energy, I was a student of theoretical physics. I received my first degree there at the age of sixteen, wrote my first algorithms literally before I had my first date.

I have always loved to poke around in other people’s labs, exploring the next wave of fascinating ways to tackle problems. These days this penchant still allows the occasional glimpse of discoveries or applications likely to emerge as ways for investors to profit.

One of my favorite areas is our subject today.

Often in Oil and Energy Investor over the years, I’ve called the pursuit of battery and storage capacity that is expandable, adaptive, scalable, and cheap energy’s “Holy Grail.”

Well, we seem to be moving into another promising series of discoveries and applications. I have been following some very interesting developments in battery research that are paralleling something I have been saying for some time. The next generation on the battery front will roll out in a series of incremental improvements, not some singular history-altering monumental or staggering breakthrough.

Once again, it is likely not to be invention (coming up with something entirely new) that leads the move but innovation (using things that already exist but in a new way).

At stake is the most important single advance transforming how we maximize the way energy is retained, transmitted, and used.

Smart Money Is Hard at Work Here

A promising innovation I have been following may just hold the key for realizing the next generation of batteries. It combines work being undertaken at several locations and I have visited several of them to see firsthand.

Last week, Daniel Oberhaus writing in WIRED nicely digested what is taking place. Daniel’s summary followed a conference call I had with several of the main researchers in an intriguing approach I have been following for almost five years.

One of the leaders here is Sila Nanotechnologies, founded almost a decade ago by Gene Berdichevsky. Gene used to be the leader of the team that designed Tesla Inc.‘s (NASDAQ:TSLA) first family of lithium-ion batteries. However, he and a few others realized that a different approach is necessary for the industry to overcome the problem of offsetting battery life with the amount of energy they contain.

Sila’s approach to building a better battery is to introduce nanoengineered particles of silicon to supercharge lithium-ion cells when used as the battery’s negative electrode, or anode. Today, Sila is one of a handful of companies racing to bring lithium-silicon batteries out of the lab and into the real world, where they promise entire ranges of applications.

As Daniel puts it, the long-term goal is high-energy electric vehicles (EVs) to transform transport, but the first stop will be small devices. By this time next year, Gene plans to have the first lithium-silicon batteries in consumer electronics, which he says will make them last 20 percent longer per charge.

Now, here is the intriguing part.

Both silicon and lithium are already there in portable consumer electronics. Any cell phone, laptop, or other device will have a lithium-ion battery providing power and a silicon-based circuit board routing them to applications.

However, combining the two in a battery has been a source of major problems in the past. That’s because a charging lithium-ion battery has the ions flowing to an anode usually made of a form of carbon called graphite. If you swap graphite for silicon, far more lithium ions can be stored in the anode, which increases the energy capacity of the battery. But packing all these lithium ions into the electrode causes it to expand, often by a factor of four.

The swollen anode can pulverize the nanoengineered silicon particles and rupture the protective barrier between the anode and the battery’s electrolyte, which transports the lithium ions between the electrodes. Over time, crud builds up at the boundary between the anode and electrolyte. This both blocks the efficient transfer of lithium ions and takes many of the ions out of service. It quickly kills any performance improvements the silicon anode provided.

One way out of this problem is to sprinkle small amounts of silicon oxide-better known as sand-throughout a graphite anode. This is what Tesla currently does with its batteries. Silicon oxide comes “pre-puffed” (and actual technical term, by the way), so it reduces the stress on the anode from swelling during charging. But it also limits the amount of lithium that can be stored in the anode. Juicing a battery this way isn’t enough to produce double-digit performance gains, but it’s better than nothing.

The key is getting the best of silicon and graphite without the loss of energy capacity. At NanoGraf, another small startup pioneering in the field, energy is being boosted in carbon-silicon batteries by embedding silicon particles in graphene.

I am still a strong believer in graphene being one of the most significant discoveries of the past two decades, to occupy a fundamental role in the radical transformation of energy use. But that is a conversation for another time.

NanoGraf’s contribution to the battery transformation is applying a graphene matrix to give silicon room to swell and to protect the anode from damaging reactions with the electrolyte. Company designs point to a graphene-silicon anode increasing the amount of energy in a lithium-ion battery by up to 30 percent.

A Big Problem with a (Very) Small Solution

Yet to push that number to higher levels, graphite needs to be replaced. Researchers have been able to make silicon anodes for years, but they have struggled to scale the advanced nanoengineering processes involved in manufacturing them.

Sila has successfully figured out how to mass-manufacture silicon nanoparticles. Their solution involves packing silicon nanoparticles into a rigid shell, which protects them from damaging interactions with the battery’s electrolyte. The inside of the shell is basically a silicon sponge, and its porosity means it can accommodate swelling when the battery is charging.

This parallels a process used by New Orleans-based Advano, where they are producing silicon nanoparticles in very large amounts. To lower costs, Advano uses as raw material silicon wafer scrap from companies that make solar panels and other electronics. The chemical process employed grinds the wafers down into highly engineered nanoparticles that can be used for battery anodes.

As Advano head Alexander Girau put it in a conversation last week, the real problem is not ending up with a more powerful battery. Rather, the real issue is coming up with a battery cheap enough to allow trillions of them to be produced. With his scrap-to-anode approach, Alexander believes he has a solution.

So far, none of these companies has seen their anode material used in a consumer product, but each is in talks with battery manufacturers to make it happen. Sila expects its anodes to be in unnamed wireless earbuds and smartwatches within a year. Advano, which counts an iPod cocreator among its investors, is also in talks to have its anodes placed in consumer electronics in the near future. It is still a reach to electric vehicles (EVs), but proving the tech works in gadgets is a genuine step in that direction.

The pace of battery development is frustratingly slower than, say, advances in computers, in large measure because of a complicated web of problems arising when attempting to replace graphite with silicon in the anodes. It involves the need to increase energy density, while avoiding a reduction in the battery’s charge rate, life span, or thermal stability – keeping it from getting too hot.

Therefore, companies are first targeting the more directly obtainable introductions of silicon-lithium batteries in small consumer electronics.

The battery improvements being applied this year in such products would add 100 to 150 miles per charge to an EV. That provides the driving range necessary for widespread expansion of electric vehicles.

However, the jump from small handheld devices to EVs is a huge one. Small commercial batteries need last only a few years. EVs require batteries that last more than a decade, can handle daily recharging, a wide range of temperatures, and other unique stress elements. Building a lithium-silicon battery that retains its high energy over longer time spans is a much greater challenge.

Nonetheless, what has been underway in silicon-lithium battery applications are flat-out inspiring.

Kent Moors
Kent

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