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Influit moves to commercialize its ultra-high density liquid batteries
Loz Blain

Illinois Tech spinoff Influit Energy says it's coming out of stealth mode to commercialize a rechargeable electrofuel – a non-flammable, fast-refuelling liquid flow battery that already carries 23% more energy than lithium batteries, at half the cost.

Very much targeted at vehicles and aircraft, Influit's "nanoelectrofuels" offer an alternative to current battery tech with what appears to be a pretty compelling list of pros and cons. 

The company pitches its tech as a new type of flow battery – we've written plenty about these in the past; typically they involve two chemical liquids that are pumped over opposing sides of an ion exchange membrane to create a flow of electric current. Energy density tends to be low, because only so much battery material can be dissolved in a liquid before it starts to settle at the bottom of the tank, making it useless. This low density tends to relegate flow batteries to big, slow, cheap grid-level storage system projects and the like.

Influit says it solves this issue by using infinteissimally tiny solid nanoparticles of active metal oxide battery material suspended, rather than dissolved, in its base fluid, such that random Brownian motion alone is enough to keep the particles from settling to the bottom. It claims its nanoparticles are surface-modified to prevent agglomeration and reduce the viscosity of the solution, to the point where its electrofuels flow more or less like motor oil.

The flow battery design passes anolyte and catholyte liquids past each other on either side of an ion exchange membrane to generate current. The system needs four tanks, for spent and unspent fuels, and it works in reverse when electricity is fed back into the system

This will require a whole ecosystem; Influit is developing not only the electrofuel liquids, but the fuel cell-like onboard devices that'll extract energy from those fuels, the complex tank and fuel management systems that will keep the fluids separate and retain the spent fuel for recycling, the electrofuel retail equipment, the systems needed to "recharge" spent fuel, and the refineries needed to manufacture these nanofuel liquids in the first place. 

There will be multiple ways to top up once you're running low. "Rapid refueling pods" will offer the ability to straight-up swap spent fuel out and put fresh stuff back in. But influit says you won't lose your ability to plug in and recharge the fuel in the same way EV owners do now – either slowly through a wall socket, or rapidly through a higher-power charging station.

And there are other advantages, too; Influit says its fuels are non-flammable and non-explosive – indeed, poured on a fire, they'll actually put it out. In a catastrophic containment failure that allows the anolyte and catholyte liquids to mingle, there's a slight increase in temperature for a little while and that's about it. They work happily across a wide range of operating temperatures between -40 to 80 °C (-40 - 176 °F). They use no lithium, no heavy metals or rare Earth minerals, making them much cheaper – but also making sure source materials are abundant, and supply lines don't have to run through geopolitical leverage points like China. 

Fast fuel refilling will require four nozzles, to push in the two charged electrolytes and pull out the two spent electrolytes

Then there's energy density. Influit says its Gen1 system will offer 23% higher energy density by volume than lithium-ion – that's somewhere between 350-550 Wh/l at the system level, not just the electrolytes – and will cost half as much, although it's unclear by what metric. 

And it doesn't stop there; the Gen2 system under development promises a massive 4-5X higher energy density than lithium-ion, at a third the cost. In terms of specific energy by weight, we're talking a whopping 550-750 Wh/kg – again at the entire system level – for the next-gen system, which, once proven, would make these electrofuels very interesting to clean aviation types as well as automotive and marine concerns.

Influit has progressed to this point largely funded by US military and government agencies to the tune of over US$12 million; DARPA is very interested in non-flammable, quick-refueling electrification options for obvious reasons, and Influit is developing an EV to demonstrate its system. DARPA is also kicking in to help optimize and scale up manufacturing, hoping to reduce the mass and volume of the battery systems in the process.

NASA has funded the development of fast charging systems, and the US Air Force has funded work on the refueling nozzles and control systems, as well as contributing toward the development of that super-high density Gen2 fuel system. And Influit says it's already demonstrated a nanoelectrofuel battery system for an electric utility vehicle at the premises of another commercialization partner.

“[Influit Energy’s research] started back in 2009 as a basic science investigation when we were at Illinois Tech and Argonne National Laboratory, and we have taken our technology from basic science development, to applied science, to building prototypes, and now our first product development,” says Influit co-founder and CEO John Katsoudas in a press release.

“Everything we’re doing right now," he continues, "is geared toward the specific goal of developing what we call the closed-loop energy cycle, whereby your batteries are not solid materials, they are liquids. You can treat the battery as a fuel that gets pumped in to mobility devices—cars, trucks, airplanes, anything that needs to be electrified. Every one of our contracts is funding a different aspect of the totality development of that ecosystem. All of the technology has come together – we have a crystal-clear path before us.”

It's not a short path. The company is now actively seeking venture capital funding to take its ecosystem development to the next level. It's hiring scientists, and looking to move to an office ten times the size of its current digs, be it at home in Illinois or potentially down in Austin, Texas.

Clearly, plenty remains to be proven here, from the total system energy density right through the the charge-cycle lifespan of the fuel and how long the "fuel cells" are able to operate without becoming glugged up and needing maintenance or parts replacements. But if development pans out and Influit's batteries do what they say on the tin – at half to a third the total system price of today's lithium batteries – there's potential here for a revolutionary reshaping of electric energy storage. 

It certainly won't be coming overnight – and it's hard to imagine what else is waiting in the wings that might make these liquid batteries obsolete before they're available. But it seems like one to keep an eye on!

Source: Illinois Tech




Loz has been one of our most versatile contributors since 2007. Joining the team as a motorcycle specialist, he has since covered everything from medical and military technology to aeronautics, music gear and historical artefacts. Since 2010 he's branched out into photography, video and audio production, and he remains the only New Atlas contributor willing to put his name to a sex toy review. A singer by night, he's often on the road with his acappella band Suade.

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