Chemists propose spinach as a better, cheaper battery catalyst

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.

spinach
Credit: Ataly/Shutterstock
  • 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.


    As we look to power tomorrow's devices sustainably and economically, there's a great deal of research going into the development of better, cleaner battery technology. Showing particular promise are fuel-cell and metal-air battery technologies. Though both continue to operate using the anode/cathode/electrolyte paradigm of current batteries, the race is on to find more sustainable materials that can replace those in current use. A new study published in the American Chemical Society's open-source journal ACS Omega proposes that one solution may be Popeye's favorite superfood: spinach.

    Cathodes and anodes, oh my

    Flow of energy when battery is in use, discharging

    Credit: VectorMine/Shutterstock/Big Think

    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 "redox."

    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.

    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 round and round the battery-device circuit. (When charging a battery, electrons go in the opposite direction connected to a charger.)

    The new study is concerned with the catalyst that produces the cathode's oxygen reduction reaction.

    Replacing a problematic, pricey catalyst

    platinum bricks

    Credit: AlexLMX/Shutterstock

    Fuel cell batteries and metal-air batteries 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.

    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."

    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.

    Enter spinach

    Credit: Liu, et al./ACS Omega 2020, 5, 38, 24367-24378

    Shouzhong Zou, of American University's Department of Chemistry, is the paper's senior author. The lead author is Xiaojun Liu, with Wenyue Li as co-author. Professor Zou reports:

    "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."

    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.

    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.

    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 melamine, 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 pyrolized twice.

    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.

    "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.

    Finally, Zou understandably hopes to develop a simple, less energy-intensive way to make their catalyst nanosheets.

    Iron Age discoveries uncovered outside London, including a ‘murder’ victim

    A man's skeleton, found facedown with his hands bound, was unearthed near an ancient ceremonial circle during a high speed rail excavation project.

    Photo Credit: HS2
    Culture & Religion
    • A skeleton representing a man who was tossed face down into a ditch nearly 2,500 years ago with his hands bound in front of his hips was dug up during an excavation outside of London.
    • The discovery was made during a high speed rail project that has been a bonanza for archaeology, as the area is home to more than 60 ancient sites along the planned route.
    • An ornate grave of a high status individual from the Roman period and an ancient ceremonial circle were also discovered during the excavations.
    Keep reading Show less

    Are we really addicted to technology?

    Fear that new technologies are addictive isn't a modern phenomenon.

    Credit: Rodion Kutsaev via Unsplash
    Technology & Innovation

    This article was originally published on our sister site, Freethink, which has partnered with the Build for Tomorrow podcast to go inside new episodes each month. Subscribe here to learn more about the crazy, curious things from history that shaped us, and how we can shape the future.

    In many ways, technology has made our lives better. Through smartphones, apps, and social media platforms we can now work more efficiently and connect in ways that would have been unimaginable just decades ago.

    But as we've grown to rely on technology for a lot of our professional and personal needs, most of us are asking tough questions about the role technology plays in our own lives. Are we becoming too dependent on technology to the point that it's actually harming us?

    In the latest episode of Build for Tomorrow, host and Entrepreneur Editor-in-Chief Jason Feifer takes on the thorny question: is technology addictive?

    Popularizing medical language

    What makes something addictive rather than just engaging? It's a meaningful distinction because if technology is addictive, the next question could be: are the creators of popular digital technologies, like smartphones and social media apps, intentionally creating things that are addictive? If so, should they be held responsible?

    To answer those questions, we've first got to agree on a definition of "addiction." As it turns out, that's not quite as easy as it sounds.

    If we don't have a good definition of what we're talking about, then we can't properly help people.

    LIAM SATCHELL UNIVERSITY OF WINCHESTER

    "Over the past few decades, a lot of effort has gone into destigmatizing conversations about mental health, which of course is a very good thing," Feifer explains. It also means that medical language has entered into our vernacular —we're now more comfortable using clinical words outside of a specific diagnosis.

    "We've all got that one friend who says, 'Oh, I'm a little bit OCD' or that friend who says, 'Oh, this is my big PTSD moment,'" Liam Satchell, a lecturer in psychology at the University of Winchester and guest on the podcast, says. He's concerned about how the word "addiction" gets tossed around by people with no background in mental health. An increased concern surrounding "tech addiction" isn't actually being driven by concern among psychiatric professionals, he says.

    "These sorts of concerns about things like internet use or social media use haven't come from the psychiatric community as much," Satchell says. "They've come from people who are interested in technology first."

    The casual use of medical language can lead to confusion about what is actually a mental health concern. We need a reliable standard for recognizing, discussing, and ultimately treating psychological conditions.

    "If we don't have a good definition of what we're talking about, then we can't properly help people," Satchell says. That's why, according to Satchell, the psychiatric definition of addiction being based around experiencing distress or significant family, social, or occupational disruption needs to be included in any definition of addiction we may use.

    Too much reading causes... heat rashes?

    But as Feifer points out in his podcast, both popularizing medical language and the fear that new technologies are addictive aren't totally modern phenomena.

    Take, for instance, the concept of "reading mania."

    In the 18th Century, an author named J. G. Heinzmann claimed that people who read too many novels could experience something called "reading mania." This condition, Heinzmann explained, could cause many symptoms, including: "weakening of the eyes, heat rashes, gout, arthritis, hemorrhoids, asthma, apoplexy, pulmonary disease, indigestion, blocking of the bowels, nervous disorder, migraines, epilepsy, hypochondria, and melancholy."

    "That is all very specific! But really, even the term 'reading mania' is medical," Feifer says.

    "Manic episodes are not a joke, folks. But this didn't stop people a century later from applying the same term to wristwatches."

    Indeed, an 1889 piece in the Newcastle Weekly Courant declared: "The watch mania, as it is called, is certainly excessive; indeed it becomes rabid."

    Similar concerns have echoed throughout history about the radio, telephone, TV, and video games.

    "It may sound comical in our modern context, but back then, when those new technologies were the latest distraction, they were probably really engaging. People spent too much time doing them," Feifer says. "And what can we say about that now, having seen it play out over and over and over again? We can say it's common. It's a common behavior. Doesn't mean it's the healthiest one. It's just not a medical problem."

    Few today would argue that novels are in-and-of-themselves addictive — regardless of how voraciously you may have consumed your last favorite novel. So, what happened? Were these things ever addictive — and if not, what was happening in these moments of concern?

    People are complicated, our relationship with new technology is complicated, and addiction is complicated — and our efforts to simplify very complex things, and make generalizations across broad portions of the population, can lead to real harm.

    JASON FEIFER HOST OF BUILD FOR TOMORROW

    There's a risk of pathologizing normal behavior, says Joel Billieux, professor of clinical psychology and psychological assessment at the University of Lausanne in Switzerland, and guest on the podcast. He's on a mission to understand how we can suss out what is truly addictive behavior versus what is normal behavior that we're calling addictive.

    For Billieux and other professionals, this isn't just a rhetorical game. He uses the example of gaming addiction, which has come under increased scrutiny over the past half-decade. The language used around the subject of gaming addiction will determine how behaviors of potential patients are analyzed — and ultimately what treatment is recommended.

    "For a lot of people you can realize that the gaming is actually a coping (mechanism for) social anxiety or trauma or depression," says Billieux.

    "Those cases, of course, you will not necessarily target gaming per se. You will target what caused depression. And then as a result, If you succeed, gaming will diminish."

    In some instances, a person might legitimately be addicted to gaming or technology, and require the corresponding treatment — but that treatment might be the wrong answer for another person.

    "None of this is to discount that for some people, technology is a factor in a mental health problem," says Feifer.

    "I am also not discounting that individual people can use technology such as smartphones or social media to a degree where it has a genuine negative impact on their lives. But the point here to understand is that people are complicated, our relationship with new technology is complicated, and addiction is complicated — and our efforts to simplify very complex things, and make generalizations across broad portions of the population, can lead to real harm."

    Behavioral addiction is a notoriously complex thing for professionals to diagnose — even more so since the latest edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM-5), the book professionals use to classify mental disorders, introduced a new idea about addiction in 2013.

    "The DSM-5 grouped substance addiction with gambling addiction — this is the first time that substance addiction was directly categorized with any kind of behavioral addiction," Feifer says.

    "And then, the DSM-5 went a tiny bit further — and proposed that other potentially addictive behaviors require further study."

    This might not sound like that big of a deal to laypeople, but its effect was massive in medicine.

    "Researchers started launching studies — not to see if a behavior like social media use can be addictive, but rather, to start with the assumption that social media use is addictive, and then to see how many people have the addiction," says Feifer.

    Learned helplessness

    The assumption that a lot of us are addicted to technology may itself be harming us by undermining our autonomy and belief that we have agency to create change in our own lives. That's what Nir Eyal, author of the books Hooked and Indistractable, calls 'learned helplessness.'

    "The price of living in a world with so many good things in it is that sometimes we have to learn these new skills, these new behaviors to moderate our use," Eyal says. "One surefire way to not do anything is to believe you are powerless. That's what learned helplessness is all about."

    So if it's not an addiction that most of us are experiencing when we check our phones 90 times a day or are wondering about what our followers are saying on Twitter — then what is it?

    "A choice, a willful choice, and perhaps some people would not agree or would criticize your choices. But I think we cannot consider that as something that is pathological in the clinical sense," says Billieux.

    Of course, for some people technology can be addictive.

    "If something is genuinely interfering with your social or occupational life, and you have no ability to control it, then please seek help," says Feifer.

    But for the vast majority of people, thinking about our use of technology as a choice — albeit not always a healthy one — can be the first step to overcoming unwanted habits.

    For more, be sure to check out the Build for Tomorrow episode here.

    Why the U.S. and Belgium are culture buddies

    The Inglehart-Welzel World Cultural map replaces geographic accuracy with closeness in terms of values.

    According to the latest version of the Inglehart-Welzel World Cultural Map, Belgium and the United States are now each other's closest neighbors in terms of cultural values.

    Credit: World Values Survey, public domain.
    Strange Maps
    • This map replaces geography with another type of closeness: cultural values.
    • Although the groups it depicts have familiar names, their shapes are not.
    • The map makes for strange bedfellows: Brazil next to South Africa and Belgium neighboring the U.S.
    Keep reading Show less
    Quantcast