The Chemistry and Potential of Sodium Batteries in Sustainable Energy Storage

First published 2024

In the early 20th century, Britain’s Royal Navy encountered a significant dilemma. Their shift from coal—a domestic resource—to oil, which needed to be imported, placed them in a precarious position concerning energy security. Drawing a parallel to today, the global community finds itself at a similar crossroads. To mitigate the devastating effects of climate change, there is a pressing need to transition from fossil fuels to low-carbon electricity. This shift necessitates the extensive use of batteries, especially for applications like vehicles and grid storage. At present, lithium-ion batteries dominate the scene, heralded for their blend of minimal upkeep and impressive energy density. For instance, their compactness, attributed to lithium being the third-lightest element, has made them indispensable in products ranging from iPhones to EVs. However, a deeper evaluation reveals an impending concern—lithium’s limited availability and the concentration of its refining processes in China. Such a centralised supply chain introduces geopolitical vulnerabilities, reminiscent of Britain’s earlier concerns with oil. A poignant example is China’s decision in October 2023 to restrict graphite exports, emphasising the potential disruptions in the lithium-ion supply chain.

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Emerging as a promising alternative are sodium batteries. Sodium, similar to lithium in its chemical properties, offers several advantages that make it a contender in the battery landscape. For one, it is found in the salt of seawater, making it vastly more abundant and cost-effective than lithium. Several Chinese firms, recognising sodium’s potential, are already harnessing it for battery production. Moreover, sodium batteries present an edge in environmental and ethical dimensions. The majority of lithium batteries require cobalt and nickel, materials fraught with ethical concerns. Nickel, like lithium, is scarce, and its terrestrial mining is ecologically harmful. The societal implications are also concerning, with a significant portion of the world’s cobalt originating from the Democratic Republic of Congo, where child labour is rampant, and working conditions are deplorable. In contrast, sodium batteries can incorporate electrodes derived from iron and manganese—materials that are both abundant and devoid of such ethical issues.

However, the adoption of sodium technology is not without challenges. The most immediate is the weight factor. Being denser, sodium batteries are inherently heavier than their lithium counterparts. While this might be inconsequential for applications like grid storage, it becomes a significant concern in sectors where weight is a decisive factor, such as aviation. Moreover, lithium-ion batteries have enjoyed a considerable developmental head start. Commercialised in the 1990s, they have had the benefit of extensive research and investment, leading to consistent advancements in efficiency and cost-effectiveness. In comparison, sodium batteries are still in their nascent stages, making their widespread adoption contingent on accelerated research and developmental efforts.

Taking a leaf from history, Churchill’s assertion on the importance of diversified energy sources is more relevant now than ever. As countries pledge vast resources towards green initiatives, it becomes crucial to diversify investments across various battery technologies, encompassing sodium. Only through such a multifaceted approach can nations insulate themselves from potential supply chain disruptions, ensuring both energy security and progress towards climate objectives. In essence, while lithium-ion batteries have undeniably paved the way in the realm of energy storage, the future might just see a more diverse array of solutions, with sodium batteries playing a pivotal role.

Diving deeper into the realm of sodium batteries, one cannot ignore the underlying chemistry that makes this technology a contender in the energy storage field. Sodium-ion batteries function similarly to lithium-ion batteries in their basic mechanism. At their core, both rely on the shuttling of ions between the anode and cathode during charging and discharging cycles. Specifically, in sodium-ion batteries, sodium ions travel from the cathode through an electrolyte and embed themselves in the anode during the charging process. When the battery discharges, these ions travel back to the cathode, releasing energy in the process.

The choice of materials for the electrodes and the electrolyte plays a crucial role in determining the efficiency, lifespan, and safety of the battery. The majority of sodium-ion battery research focuses on finding suitable anode materials that can efficiently host sodium ions. One common candidate is hard carbon, which, when sourced from sustainable resources, could further underscore the environmental benefits of sodium-ion batteries. For instance, research has delved into deriving hard carbon from biomass, which not only ensures a renewable source but also addresses waste management issues, presenting a dual benefit.

Yet, the chemistry of sodium presents unique challenges. Sodium ions are larger than lithium ions, which can pose difficulties in the insertion and extraction process, potentially affecting the battery’s cycle life. There’s also the matter of the voltage window. While lithium-ion batteries can operate at higher voltages, sodium-ion batteries have a more restricted voltage range due to the possibility of sodium metal plating at the anode. This plating can cause internal short circuits and poses safety risks. However, researchers are making strides in addressing this issue by exploring alternative electrolytes and electrode materials.

Another facet of sodium battery chemistry that warrants attention is the thermal stability. Historically, lithium-ion batteries have been associated with overheating and, in rare cases, combustion. In contrast, preliminary research suggests that sodium-ion batteries might offer improved thermal stability, reducing the risk of thermal runaway and potential safety hazards.

In evaluating the potential of sodium batteries, it becomes evident that the advantages offered by sodium’s abundance and the prospective ethical and environmental benefits are counterbalanced by the technical challenges inherent to sodium’s chemistry. As with any emerging technology, ongoing research and innovation are paramount. The journey towards making sodium-ion batteries a mainstream solution will undoubtedly be marked by trials, errors, and breakthroughs. Yet, the promise they hold in democratising energy storage and furthering sustainable solutions makes this journey not just necessary, but imperative.

Links

https://www.csis.org/analysis/chinas-new-graphite-restrictions

https://www.flashbattery.tech/en/sodium-batteries/

https://www.spglobal.com/marketintelligence/en/news-insights/latest-news-headlines/batteries-metal-supply-concerns-push-ev-makers-to-new-battery-chemistries-75884340

Bioluminescence: From Nature to Technology

First published 2024

The fascination with bioluminescence, where organisms emit light due to chemical reactions within them, has gripped both the human imagination and scientific inquiry for centuries. Ancient historical documents reveal that early civilizations recognised the health benefits of luminescent organisms. Pliny the Elder’s first-century writings discuss the medicinal advantages of consuming pulmo marinus, a luminous jellyfish, suggesting an early intersection of natural history with medical science. These accounts, while lacking scientific rigour by modern standards, mark an important point in the history of medicine. Similarly, the Greek physician Dioscorides noted the benefits of applying these glowing creatures topically for certain ailments, incorporating them into early medical treatments.

As anecdotal remedies evolved into scientific understanding, the understanding of bioluminescence underwent significant transformation with the identification of its biochemical roots. Discoveries about the interaction between luciferase and luciferin enzymes, and the role of symbiotic bacteria in light production, revealed the mechanism behind the enigmatic glow of deep-sea fish, shallow-water jellyfish, and terrestrial fireflies. This led to a distinction between bioluminescence and biofluorescence—organisms like jellyfish absorb and re-emit light—which furthered research in living light. Such distinctions have had significant implications in medical research, such as using bioluminescent markers to track cancer cell progression, shifting from simple curiosity to practical application.

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In 2016, a study from the Russian Academy of Sciences and the Pirogov Russian National Research Medical University highlighted the numerous medical applications derived from bioluminescence. Techniques such as immunoassays and bioimaging are just a few sophisticated tools that have resulted. The isolation of Green Fluorescent Protein from jellyfish, for example, has significantly advanced biological research, representing a paradigm shift in scientific methodologies.

The use of bioluminescent and fluorescent proteins has notably impacted neuroscience. Researchers like Vincent Pieribone have developed methods to map brain activity by tagging neurons with fluorescent markers. Techniques such as the ‘brainbow’, where neurons are tagged with a spectrum of fluorescent markers, illuminate the intricate networks of the brain, once a domain relegated to science fiction. This groundbreaking method enables the distinction of individual cells amidst a labyrinth of neural connections, facilitating a deeper understanding of brain function. Similarly, the development of genetically encoded fluorescent voltage indicators (GEVIs) allows real-time visualisation of nerve cell activity, offering a window into the previously opaque processes of the living brain.

Beyond neuroscience, these discoveries have practical medical applications, like the detection of bilirubin levels in the liver, employing fluorescent proteins derived from eels. The unusual biofluorescence of certain eels, tied to their unique management of biliverdin and bilirubin, provides a novel avenue for non-invasive medical diagnostics. This link between natural phenomena and medical technology not only underscores the potential of bioluminescence in health care but also highlights the serendipitous nature of scientific discovery.

Bioluminescence’s reach extends into biotechnology, where it is crucial for ATP sensing. The efficiency of the firefly luciferase and D-luciferin reaction in light emission in ATP’s presence has become essential in assays to measure ATP concentration. Despite some challenges, like the quick decay of light, modifications have been made to stabilise and improve the assays. The light emitted by this reaction peaks rapidly but decays quickly, which is a challenge that researchers have managed by using stabilisers and ensuring the use of pure samples. Despite the decay, the emitted light remains proportional to ATP levels within a certain range, making it an invaluable asset for investigating cellular energy fluctuations and ATP-dependent biochemical pathways.

Moreover, these assays are not uniform; they are crafted to cater to various sensitivities and applications, offering a spectrum from constant light emission to high-sensitivity variants, enhancing the flexibility of their use. For instance, ATP detection kits are leveraged for hygiene control, ensuring clinical and food safety by swiftly gauging surface cleanliness. This application is particularly critical given its rapidity compared to traditional microbial culture methods, allowing immediate and informed decisions regarding sanitation practices. Furthermore, adaptations of this technology have resulted in portable devices compatible with smartphones, significantly expanding the practicality and accessibility of ATP bioluminescent assays for real-time monitoring.

The environmental applications of bioluminescence are equally compelling. Bioluminescent bacteria are harnessed as living detectors of ecosystem health, providing quick feedback on the toxicity levels within an environment by correlating light output with bacterial respiratory activity. The innovation in this area lies in the design of sensors that either continuously register light variations or are inducible based on the specific toxins present. This has profound implications for ecological monitoring, with the potential for early detection of pollutants that could otherwise go unnoticed until they cause significant harm.

In the realm of medical applications, bioluminescence imaging (BLI) has emerged as a highly sensitive modality for visualising internal biological processes in live animals without the invasiveness of traditional methods. The real-time tracking of genetically modified cells or pathogens marked with luciferase genes has proved to be crucial in studying the progression and treatment of various diseases. However, the field continues to grapple with challenges such as achieving sufficient brightness for optimal imaging depth and resolution.

The therapeutic prospects of bioluminescence are exemplified in the area of photodynamic therapy (PDT). This innovative treatment strategy uses light to activate photosensitisers, which in turn produce reactive oxygen species capable of killing cancer cells. Although the application of bioluminescence in PDT has seen both triumphs and trials, ongoing research to improve the light output and efficiency of energy transfer suggests a burgeoning future in cancer therapy.

Despite its vast applications, bioluminescence faces limitations such as emission wavelength suitability, stability, and the bioavailability of luciferins. Researchers must address these challenges to balance the sensitivity and practicality of bioluminescent probes, especially for in vivo applications.

The influence of bioluminescence has transcended science, entering public spaces and art, inspiring eco-friendly lighting and ‘living art’ installations. The commercialisation of bioluminescence reflects its broader societal impact, encouraging the pursuit of sustainable bioluminescent solutions.

In essence, bioluminescence has become an essential element across diverse scientific disciplines. Its role in diagnostics and therapeutic interventions is expanding, with continued research dedicated to refining bioluminescent tools. These ongoing advancements emphasise the wide-reaching significance of this natural phenomenon, indicating a bright future for its application in addressing complex biological and environmental issues.

Links

Kaskova Z, Tsarkova A, Yampolsky I. 2016. 1001 lights: Luciferins, luciferases, their mechanisms of action and applications in chemical analysis, biology and medicine. Chemical Society Reviews 45: 6048–6077. https://doi.org/10.1039/C6CS00296J

https://pubmed.ncbi.nlm.nih.gov/30420685/

https://www.news-medical.net/health/How-is-Bioluminescence-Used-in-Cancer-Research.aspx

https://tos.org/oceanography/article/bioluminescent-biofluorescent-species-light-the-way-to-new-biomedical-discoveries

https://www.nature.com/articles/s41598-018-38258-z

https://pubs.rsc.org/en/content/articlelanding/2021/cs/d0cs01492c

https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/10.1002/bio.955

The Impact of Tectonic Collisions on Seawater Chemistry and Climate

First published 2023

The Earth’s oceans have always been a cornerstone in shaping our planet’s climate, with their chemistry undergoing periods of stability, punctuated by brief yet transformative shifts. This link between seawater chemistry and climatic changes has profound implications for both the evolution of life and long-term atmospheric conditions. Recent studies, exploring the past 130 million years, have illuminated this deep connection, suggesting mechanisms that have been at play for over half a billion years. Geoscientists Ulrich Wortmann of the University of Toronto and Adina Paytan of the University of California Santa Cruz have been at the forefront of this groundbreaking research, emphasising the importance of seawater chemistry in understanding climatic shifts.

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The collision between the Indian subcontinent and Eurasia, occurring roughly 50 million years ago, stands as a testament to the profound effects geological events can have on our planet’s chemistry and climate. This cataclysmic encounter led to the dissolution of an extensive belt of water-soluble gypsum, which once stretched across regions from Oman to Pakistan and penetrated the heart of western India. Geologists and earth enthusiasts today can witness the echoes of this monumental event in the rugged and imposing Zagros Mountains of western Iran, which serve as a living relic of this tectonic shift.

But the implications of this event extended far beyond the terrain. The dissolution and subsequent formation of such vast gypsum reserves had a direct bearing on the oceans’ sulphate content. An alteration in these sulphate concentrations can bring about significant changes in marine ecosystems, possibly affecting biodiversity and food chains. Moreover, the sulphate content also plays a pivotal role in shaping atmospheric conditions. As the sulphate levels in the oceans vary, so does the number of sulphate aerosols in the atmosphere. These aerosols are not mere particles floating in the air; they are key actors in the Earth’s climate system, influencing temperature patterns and precipitation, thus highlighting the link between geology, ocean chemistry, and climate.

Wortmann and Paytan’s groundbreaking collaboration has brought to light a compelling hypothesis grounded in years of research and analysis. Drawing from data spanning the past 130 million years, they propose that shifts in the sulphate concentrations in the oceans act as markers for climatic change. Elevated sulphate levels, they contend, are closely associated with global cooling phases. Conversely, diminished sulphate levels often align with warmer, more greenhouse-like conditions. Central to their theory is the dissolution of vast ancient salt deposits, exemplified by the significant geological event of the India-Eurasia collision approximately 50 million years ago. This tectonic event led to the dissolution of an expansive belt of water-soluble gypsum, which had spanned regions from Oman to Pakistan and reached deep into western India. Their findings suggest that such major shifts in seawater chemistry, as observed following this collision, could have played a pivotal role in ending the Eocene epoch—a period recognised as one of the warmest in the Cenozoic era. As a result of these chemical changes, the planet began a monumental transition from a greenhouse-dominated climate to a much cooler icehouse climate, a transformation that was dramatically marked by the swift and expansive growth of the Antarctic ice sheet.

Building upon prior research, Wortmann’s insights into marine sulphate concentrations and biogeochemical cycling, paired with Paytan’s data on past seawater sulphur compositions, have enriched our understanding of the interplay between ocean chemistry and climate. These findings challenge traditional views, particularly surrounding the impact of gypsum deposits on seawater chemistry, and represent a paradigm shift in our understanding of ocean chemistry’s temporal fluctuations and their broader implications for the climate. As we move forward, acknowledging the oceans’ central role in global climate patterns becomes paramount. Protecting these vast bodies of water is not only an ecological imperative but also vital in ensuring they continue regulating our planet’s climate for the millennia to come.

Links

https://www.science.org/doi/10.1126/science.1220656

https://oceanservice.noaa.gov/facts/ocean_weather.html

https://oceanexplorer.noaa.gov/facts/climate.html

https://pubs.acs.org/doi/10.1021/acs.chemrev.5b00226