While it's always been a boon to Popeye's "muskles," it looks like spinach may also have a role to play in clean future batteries.
- Scientists are seeking sustainable, clean chemicals for use in future fuel cell and metal-air batteries.
- Platinum is the current go-to substance for battery cathode catalysts, but it poses a number of problems, including high cost and instability.
- Chemists at American University have developed a new high-performance catalyst from simple spinach, although its preparation as a catalyst is anything but simple.
Cathodes and anodes, oh my<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2OTU5MC9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNDQ0NjA0OH0.Fe2eDSkzfzSBG3bGwDsEdrxOy14JYGuhJGjm9shhtkg/img.jpg?width=980" id="5e913" class="rm-shortcode" data-rm-shortcode-id="22095dc5998edbe5c1e27ec10b5a4cc9" data-rm-shortcode-name="rebelmouse-image" data-width="681" data-height="836" />
Flow of energy when battery is in use, discharging
Credit: VectorMine/Shutterstock/Big Think<p>Electrons travel within a battery from one electrode, called the anode, through the battery's electrolyte — either a powder or liquid barrier — to another electrode, called the cathode. The anode releases these electrons through a chemical process called oxidation, while the cathode accepts them through another, an oxygen reduction reaction. Together, this exchange is called a "<a href="https://en.wikipedia.org/wiki/Redox" target="_blank">redox</a>."</p><p>The electrons' return trip back to the anode, however, requires a "load" provided by an external device, which is fine, since that device — a flashlight, a phone, or a car, for example — operates on the energy produced by the battery's electrons passing through.</p><p>The electrons travel out from the cathode's positive terminal to the device then return to the battery's negative anode terminal. In this way the energy travels <a href="https://www.explainthatstuff.com/batteries.html#parts" target="_blank">round and round</a> the battery-device circuit. (When charging a battery, electrons go in the opposite direction connected to a charger.)</p><p>The new study is concerned with the <a href="https://en.wikipedia.org/wiki/Catalysis" target="_blank" rel="noopener noreferrer">catalyst</a> that produces the cathode's oxygen reduction reaction.</p>
Replacing a problematic, pricey catalyst<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2OTU5Ni9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYxMjYyNDI1Nn0.pI9itmS82CPFV4nUOAURwP9amjNi6HpPpU2biikLxYs/img.jpg?width=980" id="9685a" class="rm-shortcode" data-rm-shortcode-id="3a29c292ad8026d129250d041f1fac9e" data-rm-shortcode-name="rebelmouse-image" alt="platinum bricks" data-width="1440" data-height="960" />
Credit: AlexLMX/Shutterstock<p><a href="https://en.wikipedia.org/wiki/Fuel_cell" target="_blank" rel="noopener noreferrer">Fuel cell batteries</a> and <a href="https://en.wikipedia.org/wiki/Metal%E2%80%93air_electrochemical_cell" target="_blank">metal-air batteries</a> use the surrounding air outside the battery as their cathode. It's clean, free, plentiful, and it works, as long as there's a catalyst that can adequately prompt the requisite oxygen reduction reaction.</p><p>The most commonly used catalysts for such batteries have been based on platinum. There are problems with these, though. Of course, platinum is expensive. Also, as the study notes, "the lack of long-term stability and the vulnerability to surface poisoning by various chemicals such as methanol and carbon monoxide, call for the development of non-Pt group metal (NPGM) catalysts."</p><p>Researchers have therefore been exploring non-toxic, carbon-based catalyst alternatives since they may be more stable and exhibit resistance to surface poisoning. And because carbon is everywhere, they'd be inexpensive to produce. However, some of the materials being investigated don't do the job as well as platinum-based catalysts. The chemical reaction they produce is slow, posing a speed bottleneck to the flow of electrons.</p>
Enter spinach<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yNDQ2OTYwMy9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYzNjIxNzI1MX0.Ru_hwAVllm7R2mCfu0X94MdVXpCYbZz3VjcfvsRMaTo/img.jpg?width=980" id="6321d" class="rm-shortcode" data-rm-shortcode-id="f8285054c63c2fc02bef8fba3b29a7cf" data-rm-shortcode-name="rebelmouse-image" data-width="1326" data-height="1280" />
Credit: Liu, et al./ACS Omega 2020, 5, 38, 24367-24378<p><span style="background-color: initial;"><a href="https://www.american.edu/cas/faculty/szou.cfm" target="_blank">Shouzhong Zou</a></span>, of American University's <a href="https://www.american.edu/cas/chemistry/" target="_blank">Department of Chemistry</a>, is the paper's senior author. The lead author is Xiaojun Liu, with Wenyue Li as co-author. Professor Zou reports:</p><p style="margin-left: 20px;">"The method we tested can produce highly active, carbon-based catalysts from spinach, which is a renewable biomass. In fact, we believe it outperforms commercial platinum catalysts in both activity and stability. The catalysts are potentially applicable in hydrogen fuel cells and metal-air batteries."</p><p>While other catalyst research has involved plants such as rice and cattails, Zou believes spinach has a few things that make it a superior candidate as a catalyst material. For one thing, it's rich in iron and nitrogen, both essential catalyst ingredients. In addition, it's easy and inexpensive to grow, and it's abundant.</p><p>Zou and his students developed spinach-based carbon nanosheets a thousand times thinner than a human hair. The process is complex, a combination of basic and advanced techniques.</p><p>To begin, the researchers washed, juiced, and freeze-dried the vegetable before grinding it by hand into a fine powder using a mortar and pestle. Next, the spinach powder was dissolved and mixed with <a href="https://en.wikipedia.org/wiki/Melamine" target="_blank">melamine</a>, sodium chloride, and potassium chloride in water and cooked together at 120°C. This mixture was then rapid-cooled in liquid nitrogen and freeze-dried. Then it was <a href="https://en.wikipedia.org/wiki/Pyrolysis" target="_blank">pyrolized</a> twice.</p><p>It may well have been worth the effort. Measurements of the resulting nanosheet indicated that it can out-perform platinum as a catalyst in both speed and stability. Of course, that's on top of being made from such an unassuming, inexpensive, and widely available plant.</p><p>"This work," says Zou, "suggests that sustainable catalysts can be made for an oxygen reduction reaction from natural resources." The next step for Zou and his students is to try out their spinach catalyst in prototype fuel cells to assess its performance in action. They're also looking into the use of other plant materials for catalysts.</p><p>Finally, Zou understandably hopes to develop a simple, less energy-intensive way to make their catalyst nanosheets.</p>
Dust sticking to things on the moon is a serious problem researchers are trying to solve.
Sticky situation<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU5OTA1Mi9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTY1MDAyMzU0MH0.lfYLUy2mETdXOgEGdyEHPUJD2aXqab9qB-WoMp94ldk/img.jpg?width=980" id="a045b" class="rm-shortcode" data-rm-shortcode-id="40f701f33214c9cfdb248d88a49d0ca9" data-rm-shortcode-name="rebelmouse-image" data-width="1440" data-height="1440" />
Microscopic view of man-made "moon dust"
Credit: IMPACT lab/CU Boulder<p>Lunar dust is not much like the stuff settling on the surfaces of your home. For one thing, Wang reports, "Lunar dust is very jagged and abrasive, like broken shards of glass."</p><p>The reason that it's so stubbornly sticky is that it carries an electric charge not unlike that of a sock you've just removed from the dryer. The charge results from being continually exposed to the Sun's radiation as the dust sits on the lunar surface unprotected by an atmosphere like ours. The moon does have very thin atmosphere that contains odd gases such as sodium and potassium, <a href="https://www.nasa.gov/mission_pages/LADEE/news/lunar-atmosphere.html" target="_blank">says NASA</a>, but it isn't thick enough to afford much protection from radiation.</p>
Overload of electrons<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="ea957f6f96e5b4796909ee398cc65658"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/-aHHWAeda6o?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>The researchers explored the idea of shooting a beam of electrons at lunar dust to fill the spaces between its particles with negative charges that could push the particles further apart, away from each other and also off a surface to which they might be adhering. Says Wang, "The charges become so large that they repel each other, and then dust ejects off of the surface."<br></p><p>To test their concept, the researchers acquired <a href="https://www.nasa.gov/sites/default/files/atoms/files/nasa_tm_2010_216446_simuserg.pdf" target="_blank">lunar regolith stimulant</a> from NASA, a substance formulated on Earth that's designed to replicate lunar dust. They placed objects of various materials that had been coated with the stuff in a vacuum chamber and fired electron beams at them. (The video above shows the dust's response.)</p><p>Speaking of the behavior of the electron-blasted dust on a number of tested surfaces, including spacesuit fabric and glass, "It literally jumps off," says lead author <a href="https://www.mendeley.com/authors/57218515747/" target="_blank" rel="noopener noreferrer">Benjamin Farr</a>. However, the finest-grained regolith, the kind that gets stuck in brushes, remained unperturbed by the electrons. Overall, the electrons cleaned off about 75 percent to 85 percent of the dust. "It worked pretty well, but not well enough that we're done," says Farr. Looking forward, the team is exploring ways in which the electron beam's cleaning power can be increased.</p><p>This is not the first attempt at using electrons to clean up lunar dust. For example, NASA has explored using <a href="https://www.seeker.com/space/exploration/new-spacesuit-system-could-repel-destructive-moon-dust" target="_blank">nanotube electrode networks</a> in spacesuits to keep dust off. <a href="https://www.nasa.gov/feature/goddard/2019/nasa-s-coating-technology-could-help-resolve-lunar-dust-challenge" target="_blank" rel="noopener noreferrer">To keep regolith off other materials</a>, NASA is also considered combining charge-dissipating indium tin oxide with paint that could then be applied to otherwise dust-collecting surfaces.</p><p>The CU Boulder team anticipates one day hanging up a spacesuit in a room or compartment where it can be bombarded with electrons for cleaning. Even more convenient would be facilities where "You could just walk into an electron beam shower to remove fine dust," says study coauthor <a href="https://www.colorado.edu/physics/mihaly-horanyi" target="_blank">Mihály Horányi</a> of CU Boulder's <a href="https://www.colorado.edu/physics/" target="_blank" rel="noopener noreferrer">Department of Physics</a>.</p>
Utilizing nuclear waste converted to diamonds, this company's batteries will reportedly last thousands of years in some cases.
- Nuclear reactor parts converted to radioactive carbon-14 diamonds produce energy.
- To keep them safe, the carbon-14 diamonds are encased in a second protective diamond layer.
- The company predicts batteries for personal devices could last about nine years.
Waste not<img type="lazy-image" data-runner-src="https://assets.rebelmouse.io/eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpbWFnZSI6Imh0dHBzOi8vYXNzZXRzLnJibC5tcy8yMzU5NDQyMS9vcmlnaW4uanBnIiwiZXhwaXJlc19hdCI6MTYyNTIyNTQxOX0.LnHH-Uj9up_14gGLMii9OpWUj3qZ4kQ3aJ9vr3YNPBQ/img.jpg?width=980" id="db1dc" class="rm-shortcode" data-rm-shortcode-id="4d54eef4ec5902b331313218f4413738" data-rm-shortcode-name="rebelmouse-image" alt="NBD battery" data-width="1095" data-height="615" />
NDB's battery as it might look as a circuit-board component
Image source: NDB<p>The nuclear waste from which NDB plans to make it batteries are reactor parts that have become radioactive due to exposure to nuclear-plant fuel rods. While not considered high-grade nuclear waste—that would be spent fuel—it's still very toxic, and there's a lot of it in a nuclear generator. According to the <a href="https://inis.iaea.org/collection/NCLCollectionStore/_Public/32/039/32039321.pdf" target="_blank">International Atomic Energy Agency</a>, the "core of a typical graphite moderated reactor may contain 2000 tonnes of graphite." (A tonne is one metric ton, or about 2,205 lbs.)</p><p>The graphite contains the carbon-14 radioisotope, the same radioisotope used by archaeologists for carbon dating. It has a <a href="https://www.radioactivity.eu.com/site/pages/RadioCarbon.htm" target="_blank">half-life of 5,730 years</a>, eventually transmuting into <a href="https://www.sciencemag.org/news/2008/01/solving-carbon-14-mystery" target="_blank" rel="noopener noreferrer">nitrogen 14</a>, an anti-neutrino, and a beta decay electron, whose charge piqued NDB's interest as a potential means of producing electricity.</p><p>NDB purifies the graphite and then turns it into tiny diamonds. Building on existing technology, the company says they've designed their little carbon-14 diamonds to produce a significant amount of power. The diamonds also act as a semiconductor for collecting energy, and as a heat sink that disperses it. They're still radioactive, though, so NDB encases the tiny nuclear power plants within other inexpensive, non-radioactive carbon-12 diamonds. These glittery lab-made shells serve as, well, diamond-hard protection at the same time as they contain the carbon-14 diamonds' radiation.</p><p>NDA plans to build batteries in a range of <a href="https://en.wikipedia.org/wiki/List_of_battery_sizes#Lithium-ion_batteries_(rechargeable)" target="_blank">standard</a>—AA, AAA, 18650, and 2170—and custom sizes containing several stacked diamond layers together with a small circuit board and a supercapacitor for collecting, storing, and discharging energy. The end result is a battery, the company says, that will last a <em>very</em> long time.</p><p>NDB predicts that if a battery is used in a low-power context, say, as a satellite sensor, it could last 28,000 years. As a vehicle battery, they anticipate a useful life of 90 years, much longer than any single vehicle will last—the company anticipates that one battery could conceivably provide power for one set of wheels after another. For consumer electronics such as phones and tablets, the company expects about nine years of use for a battery.</p><p>The company's prospective investor video explains their process in greater detail.</p>
Maybe a very big deal<span style="display:block;position:relative;padding-top:56.25%;" class="rm-shortcode" data-rm-shortcode-id="72e7ea41a1df50a12187f618eb343efc"><iframe type="lazy-iframe" data-runner-src="https://www.youtube.com/embed/ksMXbhftBbM?rel=0" width="100%" height="auto" frameborder="0" scrolling="no" style="position:absolute;top:0;left:0;width:100%;height:100%;"></iframe></span><p>"Think of it in an iPhone," NDB's Neel Naicker <a href="https://newatlas.com/energy/nano-diamond-battery-interview-ndb/?itm_source=newatlas&itm_medium=article-body" target="_blank">tells New Atlas</a>. "With the same size battery, it would charge your battery from zero to full, five times an hour. Imagine that. Imagine a world where you wouldn't have to charge your battery at all for the day. Now imagine for the week, for the month… How about for decades? That's what we're able to do with this technology."</p><p>NDB anticipates having a low-power commercial version on the market in a couple of years, followed by a high-powered version in about five. If all goes as planned, NDB's technology could constitute a major step forward, providing low-cost, long-term energy to the world's electronics and vehicles. The company says, "We can start at the nanoscale and go up to power satellites, locomotives."</p><p>The company also expects their batteries to be competitively priced compared to current batteries, including lithium ion, and maybe even cheaper once they're being produced at scale—owners of nuclear waste may even pay the company to take their toxic problem off their hands.</p><p>One company's waste becomes another's diamonds.</p>
Your television may soon get a serious upgrade.
- Researchers at the University of Colorado, Boulder confirm that a new liquid phase has been discovered.
- This liquid phase was first speculated about over a century ago by physicists Peter Debye and Max Born.
- Liquid crystals are used in many technologies, including LCD televisions.
Physicist Otto Lehman, 1907
Photo: Wikimedia Commons<p>While in the nematic phase, half of the molecules point in one direction and the other half point in the other. As there is no exact positional order, the arrangement is usually random.</p><p>Though his friend let it go, Lehmann pursued this discovery, publishing his first paper in 1889. In the 1910s, two others physicists, Peter Debye and Max Born, published papers speculating that the random ordering of crystals in the nematic phase could be manipulated to fall into a state of polar order. Solid crystals already exhibited such a property, which is known as ferroelectricity. They were right about the nematic phase, though it took some time to work out the science.</p><p>In 2017, a team of physicists based at the University of York <a href="https://pubs.rsc.org/en/content/articlelanding/2017/CP/C7CP00456G#!divAbstract" target="_blank">developed a compound</a> known as RM734. When heated to extreme temperatures it behaves like a nematic LC. At lower temperatures, a "splay" arrangement is observed.</p>
The colors in this newly discovered phase of liquid crystal shift as researchers apply a small electric field.
Credit: SMRC<p>Recently, a team at the University of Colorado, Boulder, decided to apply a weak electric field to RM734. Their <a href="https://www.pnas.org/content/early/2020/06/09/2002290117" target="_blank">research</a>, published in Proceedings of the National Academy of Sciences (PNAS), claims that a new liquid phase has finally been discovered after a century of speculation.</p><p>Physicist Noel Clark of UC Boulder <a href="https://phys.org/news/2020-06-century-scientists-liquid-phase.html" target="_blank">discusses</a> the revelation.</p><p>"It was like connecting a light bulb to voltage to test it but finding the socket and hookup wires glowing much more brightly instead. That confirmed that this phase was, indeed, a ferroelectric nematic fluid."</p>
A technician installs a 100-inch LCD TV with ambilight at Dutch electronics giant Philips' stand at Berlin's IFA Consumer Electronics trade fair 30 August 2006.
Photo: John MacDougall/AFP via Getty Images<p>This finding even shocked the team, which expected to see more entropy in the configuration.</p><p>The team believes that this new phase could be used in display technologies and computer memory, as well as enhance findings in AI. In fact, they speculate that an entirely new class of materials can be derived from this new liquid phase. That's quite an evolution from one of the original LC phases: soapy water.</p><p>--</p><p><em>Stay in touch with Derek on <a href="http://www.twitter.com/derekberes" target="_blank">Twitter</a>, <a href="https://www.facebook.com/DerekBeresdotcom" target="_blank">Facebook</a> and <a href="https://derekberes.substack.com/" target="_blank">Substack</a>. His next book is</em> "<em>Hero's Dose: The Case For Psychedelics in Ritual and Therapy."</em></p>
By leveraging the difference between lit and shadowed areas, a new energy source perfect for wearables is invented.
- Mobile devices used both indoors and out may benefit from a new energy collection system that thrives on mixed and changing lighting conditions.
- Inexpensive new collection cells are said to be twice as efficient as commercial solar cells.
- The system's "shadow effect" would also maker it useful as a sensor for tracking traffic.
For all of its promise, solar energy depends on the capture of light, and the more the better. For residents of sunny climes, that's great, with rooftop collection panels, and solar farms built by utilities in wide open, sunny spaces that can provide power to the rest of us. Now, though, a team of scientists at the National University of Singapore (NUS) has announced success at deriving energy from…shadows.
We've got plenty of them everywhere. "Shadows are omnipresent, and we often take them for granted," says research team leader Tan Swee Ching, who notes how shadows are usually anathema for energy collection. "In conventional photovoltaic or optoelectronic applications where a steady source of light is used to power devices, the presence of shadows is undesirable, since it degrades the performance of devices." His team has come up with something quite different, and Tan claims of their shadow-effect energy generator (SEG) that, "This novel concept of harvesting energy in the presence of shadows is unprecedented."
The research is published in the journal Energy & Environmental Science.
How it works
Image source: Royal Society of Chemistry/NUS
The energy produced by the SEG is generated from the differential between shadowed and lit areas. "In this work," says Tan. "We capitalized on the illumination contrast caused by shadows as an indirect source of power. The contrast in illumination induces a voltage difference between the shadow and illuminated sections, resulting in an electric current."
SEG cells are less expensive to produce than solar cells. Each SEG cell is a thin film of gold on a silicon wafer, and an entire system is a set of four of these cells arrayed on a flexible, transparent plastic film. Experiments suggest the system, in use, is twice as efficient as commercial solar cells.
An SEG cell's shadow effect works best when it is half in light and half in shadow, "as this gives enough area for charge generation and collection respectively," says co-team leader Andrew Wee. When the SEG is entirely in shadow or in light, it doesn't produce a charge.
Gold in them that shadows
To be sure, the amount of energy that NUS researchers have thus far extracted is small, but it's enough to power a digital watch. The researchers envision the SEG system harvesting ambient light to power smart phones and AR glasses that are used both outdoors and indoors. While such devices can run on solar batteries, solar is only replenished outdoors, and the SEG could "scavenge energy from both illumination and shadows associated with low light intensities to maximize the efficiency of energy harvesting," says Tan. It seems clear that we're on the cusp of the era of wearables — AR visionwear, smart fabrics, smart watches, and so on — and so Tan considers the arrival of the SEG "exciting and timely."
The researchers also note an additional application for which the SEG seems a natural: It can function as a self-powered sensor for monitoring moving objects. The shadow caused by a passing object would trigger the SEG sensor, which can then record the event.
Next up for the team is investigating constructing cells using other, less costly materials than gold to make them even less expensive to produce.