Innovations: The Little Engine That Can

How a new technology that stores hydrogen as a liquid — instead of a gas — might be the key to an affordable clean-energy car.


Toyota, Honda, General Motors, and at least a dozen other automakers are jostling to dominate the nascent market for zero-emission, hydrogen-powered vehicles. But the newest commercial hydrogen car, the Toyota Mirai, still comes in at a whopping $57,500—blame the steep expense of onboard hydrogen storage—so it’s no surprise that only a few are on the market today. Hydrogen fuel cells typically generate electricity by fusing stored hydrogen gas with oxygen. And though special tanks can store the gas at high pressures, they take up huge space under the hood and waste precious energy because so much is needed to lug them around.

But nanoengineer Joseph Wang of the University of California, San Diego, might have discovered a cheaper, more compact alternative that turns this method on its head. In a recent paper in the German journal Angewandte Chemie, Wang and his team outline a system that stores hydrogen as a space-saving liquid instead of as a bloated gas.

When they were developing this model, their biggest challenge was creating a metal catalyst that would produce enough hydrogen gas to power a car, while avoiding chemical byproduct accumulation—two factors that are crucial in keeping the cost of fuel-cell parts down. They created special 20-micron-wide particles, about as wide as a fine strand of hair, called “Janus particles,” named after the two-faced Roman god. One side is made of a catalytically active platinum powder, and the other side is coated in inert titanium. The particles are dumped into the liquid-filled tanks, where the platinum chemically reacts with hydrogen-infused salts and produces hydrogen gas. That gas production makes the particles act like tiny motors: They’re propelled forward, which stirs the fuel, prevents byproduct buildup, and ensures the process happens continuously.

The researchers’ method produced more than nine times as much hydrogen gas as liquid reactions without Janus particles. They even powered a small model car, about the size of a large beach ball. The technology could mean a substantial reduction in costs, but the team still needs to test it on consumer-sized vehicles to see whether these micromotors can really save the bright idea of hydrogen-powered cars. If the technology works, expect to see cars whirring down the highway spewing water vapor instead of smoky exhaust. 

Pain Is Temporary, But Electricity Is Forever

It’s currently impossible for many pain medications to target only problematic body parts: Rather, drugs spread throughout the body, sometimes harming healthy tissues and organs. In a study published in Science Advances this spring, researchers from Sweden showed off a proof of concept for an implantable bioelectric medical device that could deliver localized medication for years, limiting the patient’s drug exposure and achieving true, precise pain reduction. What’s more, this development has the potential to eventually treat neurological disorders like epilepsy, which affects 65 million people worldwide, by delivering relevant drugs directly to the body’s nervous system and hastening their effects.

A tubular device—surgically implanted under the skin, parallel to and alongside the spine—dispenses pain-blocking medication, which doctors can refill through a syringe as needed. The key is in having complete control over how much dosage is dispersed, which is why the device is operated electrically via an outside power source. Once the doctor flips on the power, low, measured voltage pumps the drugs into the spinal cord. The researchers successfully tested the device on rodents with nerve injuries and were able to block pain signals stemming specifically from those wounds from reaching the brain.

Elastic Energy

Back in the 20th century, when newspapers flourished, they were printed quickly and cheaply on long sheets of paper that unrolled down a large factory belt, a process called roll-to-roll (R2R). Today, digital media means there is less use of R2R, but it’s actually finding a second life in the production of solar cells. Scientists working on TREASORES, a $15 million EU-funded project to create cheap carbon-based electronics, announced this spring that they had successfully developed a prototype of a flexible solar cell module made from R2R processing. The cell, they reported, can bend to a 25-millimeter radius without breaking, and it boasts a lifetime of about 4,000 hours. But unlike conventional cells, which are heavier and cannot be readily used in bendable or flexible devices, the prototype doesn’t require scarce (and expensive) materials, using silver instead of indium. Ultimately, TREASORES plans to produce rolls about 330 feet long.

Briefcase Battles

Although the public will soon be getting its first dose of augmented reality through much-hyped devices like Oculus Rift and Microsoft’s HoloLens, militaries around the world have long been a leap ahead. Soldiers and fighter pilots have been training with augmented-reality displays, which overlay virtual data on a real-world view, for more than 50 years. But now U.K.-based defense company BAE Systems hopes to take this technology and, in its own words, “revolutionize” training and real-life battlefield operations, as well as emergency-response systems.

With the help of researchers from the University of Birmingham, BAE is developing a briefcase-sized portable command center that includes a virtual-reality headset paired with interactive gloves. Announced in May, the prototype allows a commander, interacting from anywhere in the world, to access a virtual touch screen with video feeds and real-time information collected by on-site cameras and other instruments. Users can even employ artificially intelligent avatars—think a less annoying version of Microsoft Office’s Clippy—that can collect and analyze all kinds of incoming data in order to provide a more comprehensive assessment of what factors are affecting what is happening on the ground. The commanders’ orders on navigating the battlefield or managing disaster-relief operations can be relayed directly to troops via the command center.


Neel V. Patel is a freelance journalist based in New York.

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