perpendicularly to the surface of the electrodes, like a layer cake sitting on its side. On its own, the ceramic is a good conductor but prone to cracking. The polymer, for its part, is flexible but a poor conductor. The combination allowed ions to flow as smoothly as the best existing solid-state electrolytes, but with a much lower tendency to crack. There are other hurdles to overcome. As batteries charge and discharge, wiry crystals known as dendrites can grow on the electrodes’ surface, leading to cracking and, eventually, short circuits. Scientists have long believed that these form when excess lithium ions from the cathode accumulate on the surface of the anode (rather than being absorbed). Stronger electrode materials, which would resist the cracking, are an obvious solution. In a paper published in March, however, a team led by researchers at the Massachusetts Institute of Technology concluded this understanding was flawed. Instead, they said, dendrites grow when chemical reactions change the electrode’s properties, causing them to weaken. That suggests scientists should be looking for electrodes with greater chemical stability, not just strength. Materials science can also make solid-state batteries faster. In conventional polymer electrolytes, ions can move only as fast as the surrounding polymer segments allow. A group at Oak Ridge National Laboratory in Tennessee, part of America’s Department of Energy, found a way of decoupling the two sets of movements. They achieved this by adding chemical compounds called zwitterions to polymer segments that would ordinarily be poor conductors. Although zwitterions are neutral molecules, they have charged regions that can give ions a boost. The team’s results showed that this configuration could make ions travel through the electrolyte as much as 10bn times faster. Future tests will show how it performs in a cell. One noteworthy advantage of solid-state electrolytes is that they would open the door to materials other than lithium. Sodium-ion batteries, which replace the lithium in the cathode with sodium, are especially attractive. Sodium is not only cheaper and stabler than lithium, it is 1,000 times more abundant in Earth’s crust. Unfortunately sodium atoms are bigger and heavier than those of lithium, meaning they are unlikely to embed in conventional graphite electrodes. At present, the result is a heavier battery that can store less energy. Although better electrodes can improve matters—for example hard
carbon, which is capable of absorbing sodium ions into its spongelike structure, outperforms graphite—no suitable liquid electrolytes have yet been found. A solid electrolyte would be easier to work with. For one, the decreased risk of dendrite formation in solid-state batteries would allow anodes to be made out of highly reactive sodium metal. That would allow them to store more energy per kilogram than would be possible at present. Whereas a battery with a hard carbon anode has an energy density of around 175Wh/kg, sodium metal anodes could enable densities closer to 500Wh/kg. To boost a solid-state sodium-ion battery’s capacity yet further, researchers are experimenting with removing the anode altogether. That would create space for a thicker cathode that can be packed with more sodium, in turn boosting how much energy a battery could store. Removing the anode need not be fatal to the battery’s operation. While it charges, the sodium ions would move from the cathode to another battery component known as the current collector, where they would accumulate until discharge occurs. In effect, an anode is created as the battery operates. The heady pace of progress is the product of a truly global competition to produce the best solid-state design, says Shirley Meng, a materials scientist at the University of Chicago. The contest could also revolutionise the way batteries are manufactured. For now batteries with liquid electrolytes are built by submerging electrodes in vats of solvents and using enormous amounts of energy to dry them off. Solid-state batteries made in this way develop micropores on their surfaces, increasing the odds of malfunction. Thicker electrodes are also trickier to make because they dry unevenly. So-called dry electrode manufacturing—in which dry powders are pressed together to form solid batteries—is, therefore, being taken increasingly seriously. Trials have shown that it cuts energy use by about half and manufacturing costs by about a fifth, while boosting the overall performance of the batteries. Many companies, including Tesla, a maker of batteries and EVs, and LG Energy Solution, a South Korean battery maker, are competing to be first to perfect it.
Distinguishing hype from reality is not easy. But recent developments mean that ambitious promises could be fulfilled. China’s Contemporary Amperex Technology, the world’s largest battery manufacturer, has said it will produce solid-state batteries by 2027 and plans to launch the first sodium- ion EV by the middle of this year. Samsung, a South Korean electronics company, has said it will mass produce solid-state batteries by 2027 while Toyota, a Japanese carmaker, has made a similar pledge. Ford Motors, an American car manufacturer, launched a battery-making unit this month, and plans to deliver large-scale batteries for data centres and industrial businesses by next year. In the battery-making business, these are electrifying times. ■ Curious about the world? To enjoy our mind-expanding science coverage, sign up to Simply Science, our weekly subscriber-only newsletter. This article was downloaded by zlibrary from https://www.economist.com//science-and-technology/2026/05/20/breakthroughs-for- batteries-could-soon-make-them-much-better
Science & technology | Cruise control The hantavirus outbreak is a tragedy—and a valuable data source The risk to public health remains low May 21st 2026 UNCOVERING HOW a virus spreads among a population involves some tricky detective work. The schedules of all those infected have to be carefully examined in the days or weeks around the time they fell ill, in order to work out who infected whom—and, most important, where and how. The more isolated the population, the more accurately such records can be gathered. To epidemiologists, therefore, cruise ships with onboard outbreaks are the equivalent of floating Petri dishes bursting with valuable information. The MV Hondius is the latest example. As of May 20th at least 11 cases of hantavirus were confirmed among its 147 passengers and crew; three of
those infected have died. The outbreak was caused by the Andes strain of hantavirus, a bug carried by South American rodents that causes about 100- 150 known human infections in Argentina and Chile each year. Human-to- human transmission can occur but such secondary cases are rarer still. The Hondius case study is, therefore, a valuable addition to this body of knowledge. At the moment, the original source of the onboard virus is thought to be exposure to rodent droppings or urine prior to departure. The data— including genomic sequencing of the virus—suggest that the first four cases in the outbreak may have originated that way, possibly from the same source, says Thomas Hofmann from the European Centre for Disease Prevention and Control. But there is rarely complete certainty about how an infection was picked up. People cannot recall every single interaction they have with others. It is even harder to know who used the same toilet or touched the same serving utensils at a lunch buffet. Better records of passenger interactions are needed to get to the bottom of the outbreak. The disease detectives on board were tasked with working out what sorts of interactions had occurred among the known cases, as well as between that cohort and the healthy passengers, in order to help manage the outbreak. In time, the data will also help researchers assess the odds of a particular type of contact leading to transmission of the virus (such as sharing a dinner table with someone who was already infected, or giving them a hug), which will help manage future outbreaks. Although the pieces of the puzzle are still being put together, the results so far are consistent with what was already known about the Andes strain, says Dr Hofmann. Crucially, it is not a virus that transmits easily among people, such as those that cause covid-19 and the flu. If it did, he says, there would be far more cases on the Hondius, where passengers spent a lot of time in communal indoor lounges. That being said, widespread transmission between people cannot be ruled out. In an outbreak that began in Argentina in 2018 one person unleashed a chain of transmission that ultimately infected 33 others. That outbreak has led researchers to think some people may be hantavirus “superspreaders”.
For reasons that are unclear, they may be shedding and dispersing exceptionally high quantities of the virus. Even so, the studies of the Andes strain (to which the Hondius data will soon be added) show that the virus does not have what it takes to be a pandemic threat. Genomic sequencing of samples taken over the years shows that it changes very little as it circulates in rodents. What is more, samples from the ship outbreak do not show the emergence of any adaptations that could make it better at transmitting between humans. As the typical incubation period is around three weeks and transmission generally occurs when people already have symptoms, there is usually plenty of time to find and isolate close contacts. Such measures cannot contain viruses with short incubation periods (like influenza) or that are spread by asymptomatic carriers (like covid and influenza). It remains a disease to be taken seriously: mortality can be as high as 30% even when the disease is recognised early and intensive care is available. But, thankfully, becoming infected from a rodent is rare—and from a human rarer still. ■ Curious about the world? To enjoy our mind-expanding science coverage, sign up to Simply Science, our weekly subscriber-only newsletter. This article was downloaded by zlibrary from https://www.economist.com//science-and-technology/2026/05/20/the-hantavirus- outbreak-is-a-tragedy-and-a-valuable-data-source
Science & technology | Climate modification Could microscopic spheres of silica help cool the planet? Private money is bringing new ideas—and new concerns—to solar- geoengineering research May 21st 2026 IN FEBRUARY 2024 an article in the Wall Street Journal revealed that Stardust Solutions, an Israeli startup, was developing tiny particles which, if lofted into the stratosphere in sufficient number, might be used to cool the Earth. The idea of putting stuff into the stratosphere to lower temperatures was not new; it is the most discussed of the various sunlight-blocking technologies gathered under the rubric of solar geoengineering. Stardust’s novelty was that it claimed to be developing special particles which might do particularly well. What it was that made them so super, though, remained a secret.