Wednesday, December 31, 2025
Unlocking corrosion-free Zn/Br flow batteries for grid-scale energy storage - Energy & Green Tech
Scientists
have found a way to push zinc–bromine flow batteries to the next level. By
trapping corrosive bromine with a simple molecular scavenger, they were able to
remove a major barrier to the performance and lifespan of flow batteries.
By adding a sodium sulfamate (SANa) scavenger to the electrolyte, the
researchers were able to trap the bromine (Br₂) produced during battery operation by converting it
into a brominated amine. This simple change delivered a twofold payoff: it
extended the battery life by reducing the corrosive Br₂ and made the batteries much safer for both the
environment and the people maintaining them.
After comparing it with traditional
bromine-based flow batteries, they found that while the conventional systems
showed a sharp drop in performance after only 30 cycles due to corrosion, the
newer flow battery designs operated for over 700 cycles—nearly 1,400
hours—without significant performance loss.
The findings are published in Nature Energy.
Bromine acts as both the boon and bane
Flow batteries are rechargeable
systems that store energy in liquid electrolytes held in external tanks, making
them uniquely scalable and safe for renewable energy applications.
Zinc–bromine
flow battery variants are particularly gaining traction due to their high energy
density and low-cost materials, positioning them as potential alternatives to
traditional rechargeable batteries. These batteries store and deliver
electricity by pumping liquid solutions from external tanks through a central
reaction unit.
During charging, zinc ions plate
out on the negative electrode as solid metal, while bromide ions are oxidized
to bromine at the positive electrode. These reactions reverse the dissolution
of zinc back into the liquid, and bromine reverts to bromide, releasing stored
electrical energy.
However, today's bromine-based flow
batteries struggle with short lifetimes. The bromine released during charging
eats up key parts like electrodes, pipes, and even the storage tanks. On top of
that, bromine is highly volatile and toxic, so even small leaks can pollute the
air, irritate sensitive tissues, and affect the nervous system.
After several attempts to find a perfect antidote to the problem, researchers discovered that sodium sulfamate or SANa functioned as a chemical trap and altered how bromine behaves within the battery.
SANa
initiated a disproportionation reaction—a redox process in which a single
substance is both oxidized and reduced—splitting the bromine gas and binding to
it to form a mild product, N-bromo sodium sulfamate. This reaction reduced the
concentration of free-floating bromine to an acceptable level of ~7 millimoles
per liter (mM).
The scavenger's action of binding to
bromine had a beneficial reaction: a two-electron transfer phenomenon, which
enabled the battery to store significantly more energy. The flow battery with
added SANa achieved an energy density of 152 Wh/l, compared with 90 Wh/l for
conventional versions.
To test the battery's limits, the team
designed a 5 kW stack comprising 30 individual battery cells connected in
series. They found that the newly designed flow battery achieved over 700
stable cycles. The redesigned flow battery delivered more than 700 stable
cycles and did so at a much lower cost, since it no longer required expensive
corrosion-resistant membranes, pumps, or storage tanks.
The researchers are hopeful that insights from this study can make it feasible to design mild, long-life, and high-energy-density Br-based batteries for grid-scale applications.
Source: Unlocking corrosion-free Zn/Br flow batteries for grid-scale energy storage
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Tuesday, December 30, 2025
One of NASA’s Key Cameras Orbiting Mars Takes 100,000th Image - UNIVERSE
This view of a region called Syrtis Major is from the
100,000th image captured by NASA’s Mars Reconnaissance Orbiter using its HiRISE
camera. Over nearly 20 years, HiRISE has helped scientists understand how the
Red Planet’s surface is constantly changing.
NASA/JPL-Caltech/University of Arizona
Mesas and dunes stand out in the view snapped by HiRISE, one of the imagers
aboard the agency’s Mars Reconnaissance Orbiter.
After nearly 20 years at the Red
Planet, NASA’s Mars Reconnaissance Orbiter (MRO) has snapped its 100,000th
image of the surface with its HiRISE camera. Short for High Resolution Imaging
Science Experiment, HiRISE is the instrument the mission relies on for
high-resolution images of features ranging from impact craters, sand dunes, and
ice deposits to potential landing sites. Those images, in turn, help improve
our understanding of Mars and prepare for NASA’s future human missions
there.
Captured Oct. 7, this milestone
image from the spacecraft shows mesas and dunes within Syrtis Major, a region
about 50 miles (80 kilometers) southeast of Jezero Crater, which NASA’s Perseverance rover is exploring. Scientists are analyzing the image to better
understand the source of windblown sand that gets trapped in the region’s
landscape, eventually forming dunes.
“HiRISE hasn’t just discovered how
different the Martian surface is from Earth, it’s also shown us how that
surface changes over time,” said MRO’s project scientist, Leslie Tamppari of
NASA’s Jet Propulsion Laboratory in Southern California. “We’ve seen dune fields marching along with the wind and avalanches careening down steep slopes.”
Watch highlights of images captured by HiRISE, the
high-resolution camera aboard NASA’s Mars Reconnaissance Orbiter, including its
100,000th image, showing the plains and dunes of Syrtis Major.
NASA/JPL-Caltech/University of Arizona
The subject of the 100,000th image was recommended by a high school student
through the HiWish site, where anyone can suggest parts of the
planet to study. Team members at University of Arizona in Tucson, which
operates the camera, also make 3D models of HiRISE imagery so that viewers can
experience virtual
flyover videos.
“Rapid data releases, as well as
imaging targets suggested by the broader science community and public, have
been a hallmark of HiRISE,” said the camera’s principal investigator, Shane
Byrne of the University of Arizona in Tucson. “One hundred thousand images just
like this one have made Mars more familiar and accessible for everyone.”
More about MRO
NASA’s Jet Propulsion Laboratory in
Southern California manages MRO for NASA’s Science Mission Directorate in
Washington as part of NASA’s Mars Exploration Program portfolio. Lockheed
Martin Space in Denver built MRO and supports its operations.
The University of Arizona in Tucson
operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in
Boulder, Colorado.
For more information, visit: https://science.nasa.gov/mission/mars-reconnaissance-orbiter
Source: One of NASA’s Key Cameras Orbiting Mars Takes 100,000th Image - NASA
Researchers create world's smallest programmable, autonomous robots - Robotics - Engineering
Credit: Marc Miskin, University of
Pennsylvania
Researchers
at the University of Pennsylvania and University of Michigan have created the
world's smallest fully programmable, autonomous robots: microscopic swimming
machines that can independently sense and respond to their surroundings,
operate for months and cost just a penny each.
Barely visible to the naked eye, each
robot measures about 200 by 300 by 50 micrometers, smaller than a grain of
salt. Operating at the scale of many biological microorganisms, the robots
could advance medicine by monitoring the health of
individual cells and manufacturing by helping construct microscale devices.
Powered by light, the robots carry
microscopic computers and can be programmed to move in complex patterns, sense
local temperatures and adjust their paths accordingly.
Described in Science Robotics and Proceedings
of the National Academy of Sciences, the robots operate without tethers, magnetic fields
or joystick-like control from the outside, making them the first truly
autonomous, programmable robots at this scale.
"We've made autonomous robots 10,000 times smaller," says Marc Miskin, Assistant Professor in Electrical and Systems Engineering at Penn Engineering and the papers' senior author. "That opens up an entirely new scale for programmable robots."
Credit: Michael Simari, University of
Michigan
Breaking the sub-millimeter barrier
For decades, electronics have
gotten smaller and smaller, but robots have struggled to keep pace.
"Building robots that operate independently at sizes below one millimeter
is incredibly difficult," says Miskin. "The field has essentially been
stuck on this problem for 40 years."
The forces that dominate the human
world, like gravity and inertia, depend on volume. Shrink down to the size of a
cell, however, and forces tied to surface area, like drag and viscosity, take
over. "If you're small enough, pushing on water is like pushing through
tar," says Miskin.
In other words, at the microscale,
strategies that move larger robots, like limbs, rarely succeed. "Very tiny
legs and arms are easy to break," says Miskin. "They're also very
hard to build."
So the team had to design an entirely new propulsion system, one that worked with—rather than against—the unique physics of locomotion in the microscopic realm.
Credit: Lucas Hanson and William
Reinhardt, University of Pennsylvania
Making the robots swim
Large aquatic creatures, like fish,
move by pushing the water behind them. Thanks to Newton's Third Law, the water
exerts an equal and opposite force on the fish, propelling it forward.
The new robots, by contrast, don't
flex their bodies at all. Rather, they generate an electrical field that nudges
ions in the surrounding solution. Those ions, in turn, push on nearby water
molecules, animating the water around the robot's body.
"It's as if the robot is in a
moving river," says Miskin, "but the robot is also causing the river
to move."
The robots can adjust the
electrical field that causes the effect, allowing them to move in complex
patterns and even travel in coordinated groups, much like a school of fish, at
speeds of up to one body length per second.
And because the electrodes that generate the field have no moving parts, the robots are extremely durable. "You can repeatedly transfer these robots from one sample to another using a micropipette without damaging them," says Miskin. Charged by the glow of an LED, the robots can keep swimming for months on end.
Credit: Maya Lassiter, University of
Pennsylvania
Giving the robots brains
To be truly autonomous, a robot
needs a computer to make decisions, electronics to sense its surroundings and
control its propulsion, and tiny solar panels to power everything, and all that
needs to fit on a chip that is a fraction of a millimeter in size. This is
where David Blaauw's team at the University of Michigan came into action.
Blaauw's lab holds the record for
the world's smallest computer. When Miskin and Blaauw first met at a
presentation hosted by the Defense Advanced Research Projects Agency (DARPA)
five years ago, the pair immediately realized that their technologies were a
perfect match.
"We saw that Penn Engineering's propulsion system and our tiny electronic computers were just made for each other," says Blaauw. Still, it took five years of hard work on both sides to deliver their first working robot.
The robot has a complete onboard
computer, which allows it to receive and follow instructions autonomously.
Credit: Miskin Lab, Penn Engineering; Blaauw Lab, University of Michigan
"The key challenge for the
electronics," says Blaauw, "is that the solar panels are tiny and
produce only 75 nanowatts of power. That is over 100,000 times less power than
what a smart watch consumes."
To run the robot's computer on such
little power, the Michigan team developed special circuits that operate at
extremely low voltages and bring down the computer's power consumption by more
than 1000 times.
Still, the solar panels occupy the
majority of the space on the robot. Therefore, the second challenge was to cram
the processor and memory to store a program in the little space that remained.
"We had to totally rethink the
computer program instructions," says Blaauw, "condensing what
conventionally would require many instructions for propulsion control into a
single, special instruction to shrink the program's length to fit in the
robot's tiny memory space."
Robots that sense, remember and react
What these innovations made possible is the first sub-millimeter robot that can actually think. To the researchers' knowledge, no one has previously put a true computer—processor, memory and sensors—into a robot this small. That breakthrough makes these devices the first microscopic robots that can sense and act for themselves.
The robots, each smaller than a grain of salt,
move by using an electrical field to manipulate the ions around them. They can
sense temperatures, and could potentially advance medicine by monitoring the
health of individual cells. Credit: Bella Ciervo, Penn Engineering
The robots have electronic sensors
that can detect the temperature to within a third of a degree Celsius. This
lets robots move towards areas of increasing temperature, or report the
temperature—a proxy for cellular activity—allowing them to monitor the health
of individual cells.
"To report their temperature
measurements, we designed a special computer instruction that encodes a value,
such as the measured temperature, in the wiggles of a little dance the robot
performs," says Blaauw. "We then look at this dance through a
microscope with a camera and decode from the wiggles what the robots are saying
to us. It's very similar to how honey bees communicate with each other."
The robots are programmed by pulses
of light that also power them. Each robot has a unique address that allows the
researchers to load different programs on each robot. "This opens up a
host of possibilities," adds Blaauw, "with each robot potentially
performing a different role in a larger, joint task."
Only the beginning
Future versions of the robots could
store more complex programs, move faster, integrate new sensors or operate in
more challenging environments. In essence, the current design is a general
platform: its propulsion system works seamlessly with electronics, its circuits
can be fabricated cheaply at scale and its design allows for adding new
capabilities.
"This is really just the first chapter," says Miskin. "We've shown that you can put a brain, a sensor and a motor into something almost too small to see, and have it survive and work for months. Once you have that foundation, you can layer on all kinds of intelligence and functionality. It opens the door to a whole new future for robotics at the microscale."
Provided by University of Pennsylvania
Source: Researchers create world's smallest programmable, autonomous robots
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