(Source: MIT)
Most industry batteries use graphite electrodes

Call it crazy, call it ambitious, but one thing's for sure -- startup SolidEnergy Systems Corp. is willing to think outside of the box.
I. A Struggling Technology
Today, lithium ion batteries offer the best combination of energy versus price of any commercially available battery chemistry.  As a result, they have dominated the electronics and electric vehicle markets.  But as recent damage-induced fires with the Tesla Motors Inc.'s (TSLA) Model S roadster illustrate, lithium ion cells still have a major Achilles heel -- they're fire-prone given the flammability of lithium exposed to open air and a heat source.
Efforts to replace the widely used liquid electrolyte graphite electrode lithium ion battery cells have mostly focused on either fundamentally changing the lithium material -- replacing it with a solid lithium rich polymer -- or moving away from lithium altogether.  Both approaches have major drawbacks.
SolidEnergy -- on the surface -- appears to be taking the former route, but upon closer examination its thin-film based technology is significantly different from early solid lithium-polymer battery attempts.  Notably, SolidEnergy is using a liquid electrolyte with a high-energy lithium metal electrode -- a combination that makes lithium ion batteries more efficient, but also more flammable.  Defying expectations, SolidEnergy is boldly claiming that its brand of lithium metal electrodes is actually less flammable, thanks to its unique electrode formulation.

lithium polymer
A SolidEnergy cell is seen on the left next to its high energy lithium electrode on the right.
[Image Source: MIT Tech. Review/SolidEnergy]

There are currently only a handful of lithium polymer batteries on the market -- all of which replace liquid electrolytes with a brick of solid lithium polymer.  This approach has traditionally been thought to be necessary to prevent the volatile lithium metal electrode from catching fire.  However, these solid electrolyte polymers conduct electrons more poorly than liquid alternatives, cutting the gains of switching to the higher-energy electrode.  Further, their solid state requires them to be heated before use -- which requires special electronics that bump the cost.  At the end of the day customers are left with a battery that's only marginally more efficient and much more costly.
II. An Unusual Solution
SolidEnergy is looking to shift this equation with a new high-energy electrode design.  In order to protect the flammable electrode, SolidEnergy coats it with a thin film of solid polymer similar to the kinds used in bulk in current lithium-polymer cells.
From there SolidEnergy's design diverges more sharply from past designs, using a special liquid electrolyte.  SolidEnergy uses an ionic liquid formulation, which unlike the electrolytes in traditional cells, is not very flammable.  Better still it doesn't need to be heated (like traditional liquid electrolytes) and is more efficient (like traditional liquid electrolytes), yet fights short circuits (preventing flammability like current solid electrolytes).
In short SolidEnergy's high-energy electrode, two-part (thin-film polymer, ionic liquid) electrolyte design claims to offer the best of both major classes of lithium ion batteries (solid and liquid electrolyte).

thin film polymer
By using ionic liquids and thin films -- two cutting edge materials technologies, SolidEnergy reduces the limitations of lithium-polymer cells. [Image Source: MIT]

SolidEnergy claims its prototype cells store 30 percent more energy per volume than comparable traditional lithium ion batteries, which use graphite electrodes.  What's more, the company says it expects to be able to boost energy gains to 40 percent (over traditional cells) by the time the product hits the market.
What's more SolidEnergy claims that its batteries cost only $130 per kilowatt-hour.  While official numbers on current costs are hard to come by, they're estimated to be between $250 and $500 USD per kWh, so this represents a clear and dramatic step up, if accurate, at least cutting costs in half.
These "pie-in-the-sky" sort of numbers have helped SolidEnergy suck up $4.5M USD in venture capital.  They've also drawn skepticism.

SolidEnergy has scored funding from government high-tech grants and from interested venture capitalists, but its bold performance claims have also been met with skepticism.

Jeff Dahn, professor of physics and chemistry at Dalhousie University and topic expert on battery design, told The MIT Technology Review that there's no way to independently verify SolidEnergy's claims as it's not released any precise details about its process, its cell chemistries, or its performance numbers -- other than the general claims listed above.  It's also not released commercial cells that could be broken down and tested to independently verify claim.  All of that is not unusual considering that SolidEnergy is private and a startup -- but given how unusual the company's performance claims are, it's hard not to be a bit skeptical.
III. Moving Towards the Market
But SolidEnergy founder Qichao Hu -- listed as Chief Executive Officer and President on the company homepage, and referred to as Chief Technology Officer by the MIT Tech. Review -- says his company is working to rapidly scale the technology for commercial production of cells for personal electronics.  Versus holding out to try to produce bulkier, more complex, more costly automotive battery packs, this move that could put the potentially game-changing product on the market faster and quiet the skeptics.
Mr. Hu founded the Waltham, Mass. startup shortly after receiving his Ph.D. from the Massachusetts Institute of Technology (MIT) in 2012.

Qichao Hu
After turning heads with his MIT research, Qichao Hu rolled out his own startup -- now he believes his firm is on the verge of a revolution in mobile battery tech.

SolidEnergy has selected a valuable, if troubled partner -- A123 Systems' cooperative arm, A123 Venture Technologies.  You may recall that A123 Systems fell into a controversial bankruptcy, depsite having received approximately $129M USD from a $249M USD grant from U.S. President Barack Hussein Obama's U.S. Department of Energy (DOE).

A minor portion of A123's assets -- including the Michigan battery faciltiies for automotive clients -- were initally reported to be sold for $125M USD to Johnson Controls Inc. (JCI) a veteran parts firm.  But in the aftermath of bidding, the automotive business along with other assets -- approximately 80 percent of A123's total bankruptcy valuation -- was purchased by China's Wanxiang Group Corp., a privately held Chinese conglomerate, for $256.6M USD this January.

SolidEnergy has partnered with the Chinese-owned A123Systems to commercialize the technology, which will first target the mobile device market. [Image Source: Bloomberg]

Under Wanxiang's ownership, the resulting battery firm has focused on building partnerships with startup technology firms, renting out its high-tech battery research lab space near Boston, Massachusetts.  Now that SolidEnergy has produced working prototypes, it has signed a contract with A123Systems, LLC -- the Wanxiang subsidiary -- to scale the technology up to production.

If the partnership produces the ambitious results Mr. Qichao is promising, it could mean hours of extra battery life for laptops and smartphones, and potentially $50 USD or more off their wholesale prices, from a bill of materials standpoint.

Editor's Note:
We had inititally erroneously reported that Johnson Controls acquired A123 Systems' automotive assets.  This was based on statements in an AP report.  Since that report Johnson Control gave up on that bid and Wanxiang's purchase included the auto assets.  The error has been corrected.

Sources: MIT Technology Review, SolidEnergy Systems

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