A diatom bloom
unfolds off the Kamchatka Peninsula as spring conditions drive rapid
phytoplankton growth. These blooms play an important role in ocean ecosystems,
helping transfer carbon and support marine life.
Credits: NASA
Goddard Space Flight Center / Kel Elkins
NASA’s
photos of Earth released during Artemis II's mission around the moon show our
planet against the dark backdrop of space. Auroras illuminated the thin
atmosphere, city lights dotted the outline of continents, and brown deserts
gave way to green vegetation. Are those city lights normally this bright? What
kind of clouds are swirling over the Atlantic Ocean? Is that hazy brown bit dust, or smoke, or
something else?
An Artemis
II astronaut took this picture
of Earth from the Orion spacecraft’s window after completing the translunar
injection burn. There are two auroras (top right and bottom left) and zodiacal light
(bottom right) is visible as the Earth eclipses the Sun.
This and another
photo of Earth are the first downlinked images from the Artemis II astronauts.
NASA
To dig into the mysteries of our planet Earth,
NASA has a fleet of satellites in orbit, gathering data around the clock. Join
one of these satellites — the Plankton, Aerosol, Cloud, ocean Ecosystem
satellite (PACE), which launched in February 2024 — to explore its unique views
of our home planet’s ocean, atmosphere, and land surfaces.
Simon M. King, a
sophomore studying chemical and biomolecular engineering and first author of
the study. Credit: Jorge Vidal / Rice University
As
global demand for lithium-ion batteries continues to surge, a team of Rice
University researchers has developed a faster, more energy-efficient way to
recover critical minerals from spent batteries, potentially easing supply chain
pressures and reducing environmental harm.
In a new study published in Small, researchers from Rice's Department of
Materials Science and Nanoengineering introduce a class of water-based
solutions that can extract valuable metals from battery waste in minutes rather
than hours. The work centers on aqueous solutions of amino chlorides, which
mimic the performance of commonly studied green solvents like deep eutectics,
while avoiding their key limitations.
"Traditional recycling methods
often rely on harsh acids or slow, energy-intensive processes," said the
study's first author, Simon M. King, a sophomore studying chemical and
biomolecular engineering who completed this work as a summer research fellow at
the Rice Advanced Materials Institute. "What we've shown is that you can
achieve rapid, high-efficiency metal recovery using a much simpler, water-based
system."
King worked closely with corresponding
authors Pulickel Ajayan, the Benjamin M. and Mary Greenwood Anderson Professor
of Engineering, and Sohini Bhattacharyya, a research scientist in Ajayan's lab.
Credit: Rice University Advanced Materials
Institute
Lithium-ion batteries power
everything from smartphones to electric vehicles, but recycling them remains a
major challenge. Only a small fraction of battery materials, including lithium,
cobalt, nickel and manganese, are typically recovered during the recycling
process, despite growing demand and limited global reserves.
Hydrometallurgical recycling, which
dissolves metals into solution followed by their chemical precipitation, is
considered one of the most scalable approaches. However, commonly used solvents
can be toxic and proposed green alternatives (DESs) can be inefficient. To
address this, the team explored aqueous
amino chloride salts as alternative lixiviants (leaching agents). Among the
candidates tested, a solution based on hydroxylammonium
chloride (HACl)
delivered standout performance.
"We were surprised by just how
fast the reaction occurs, especially without the involvement of high
temperatures," King said. "Within the first minute, we're already
seeing the majority of the metal extraction take place."
The HACl-based solution achieved
roughly 65% extraction of key battery metals in just one minute at room
temperature with efficiencies climbing above 75% for several metals under
slightly longer processing times. And unlike many existing approaches, the
process does not require high temperatures or long reaction times—two major
drivers of cost and environmental impact.
"A big advantage of this
system is that it works under relatively mild conditions," Ajayan said.
"That opens the door to more sustainable and scalable recycling
technologies."
The team found that replacing
traditional organic solvents with water significantly reduced viscosity,
allowing faster movement of molecules and improving reaction speed. This shift
also simplifies waste handling and lowers environmental risk.
Through a combination of
experiments and modeling, the researchers identified why the HACl solution
performs so well: While acidity and chloride ions help dissolve metals, the key
factor appears to be a built-in redox-active nitrogen center in HACl that actively participates in the
reaction.
"While the rapid metal
dissolution is very interesting, what is most exciting is that this highlights
the generic chemical properties that are the major drivers for efficient
leaching," Bhattacharyya said. "That redox capability gives it a
major advantage over other similar systems we tested."
The study also shows that factors
like solvent polarity or pH can be outweighed by the presence of reactive
chemical groups and efficient mass transport to facilitate rapid leaching.
After extraction, the team
demonstrated that the recovered metals could be reprocessed into new battery
materials, completing the recycling loop. The findings point to a broader
design strategy for next-generation recycling systems: combining low-toxicity solvents with targeted chemical functionality to maximize
efficiency.
