Powering a future of sustainable energy
By Laurel Hamers
Joaquín Rodríguez-López was jolted
into the world of electrochemistry.
When he realized in college that he
could hook up a machine to some wires
and transform chemicals into energy, he
was “completely sold,” he says.
Today, he’s tackling one big obstacle to
expanding affordable renewable energy
on the U.S. electrical grid: storage. The
flow batteries that store large amounts
of energy generated by wind and solar
power need to more efficiently hold
that energy for times when the sun isn’t
shining or the breeze dies down.
In his lab at the University of Illinois
at Urbana-Champaign, Rodríguez-López,
35, has designed a new type of material
to store electric charge in these batteries, making them more efficient. And he’s
not stopping there. “We design new ways
of looking at materials, and we design
better materials,” he says.
His collaborator at the University of
Illinois, Jeffrey Moore, praises his “deep
knowledge and … willingness to share it.”
Rodríguez-López has always had a com-munity-focused mind-set. Growing up in
Mexico, he entertained himself for hours
at home with Encyclopedia Britannica.
But at school, he says, he’d hang around
with kids who weren’t doing as well academically. He liked helping them out.
Today, he’s still drawn to collaboration, working with Moore and others
via the Joint Center for Energy Storage
Research, an initiative funded by the
U.S. Department of Energy to bring new
battery and fuel cell technology from
research labs to commercialization.
“He’s really shown an ability to get
a team working together toward a
common goal,” Moore says.
One important goal for materials
science today is to build better batteries (SN: 1/21/17, p. 22). The ubiquitous
lithium-ion battery adeptly powers cell
phones and laptops, but it’s not necessarily the best way to store the large
quantities of energy generated by wind
turbines or solar panels, Rodríguez-
Keep out Joaquín Rodríguez-López and
colleagues have designed polymers too big to
seep through the membrane between a flow
battery’s positively and negatively charged
solutions, so the battery doesn’t waste energy.
López says. So a major focus in his
lab has been on bettering the flow
A flow battery has two big tanks
loaded with solutions, one positively charged and one negatively charged. The tanks are
separated by a membrane,
where the two solutions meet
and undergo chemical reactions that generate a flow of electrons, or electric current. To make a
lithium-ion battery store more electric
charge requires scaling up its positively
and negatively charged electrodes, which
are made of expensive materials. To scale
up a flow battery, just increase the size of
the tanks for not much more cost.
“Instead of having big electrodes, you
have big tanks,” says Rodríguez-López.
It’s a simpler way to store a large amount
of power generated by wind or solar for
But in today’s flow batteries, the reac-
tion-driving particles sometimes leak
across the membrane, wasting energy.
Rodríguez-López and colleagues have
designed a new kind of bulky particle that
still dissolves well in liquid but can’t cross
the barrier. These polymers, described
in 2014 in the Journal of the American
Chemical Society, link dozens or even
hundreds of smaller units in an array of
shapes. The particles store and discharge
electric energy in the battery through
a series of chemical reactions that
progress along the polymer unit by unit,
like a flame moving up a match.
When Rodríguez-López began this
research a few years ago, it was a side
project for the Joint Center for Energy
Storage Research, where materials
scientist George Crabtree of Argonne
National Laboratory in Lemont, Ill., is
director. Today, Crabtree says, the work
is a major focus of the center.
Rodríguez-López is thinking bigger
than designing new materials, though.
He’s also using new techniques to figure
out why and how these materials behave
the way they do so he can troubleshoot
more rationally and, ultimately, get the
molecules to do exactly what he wants.
For example, he’s become an expert in
scanning electrochemical microscopy so
he can watch electrons move as chemi-
cal reactions progress along his lengthy
molecules. He uses the technique to aim
for ideal properties in his batteries.
Looking forward, Rodríguez-López
says he’d like to bring more biological
influence into his molecule-designing
work. After all, he says, cells are filled
with bulky proteins finely tuned for
specific jobs. Some can repair themselves when broken, while others can
self-destruct. Understanding nature’s
complexity, he says, could help him
design materials for batteries that react
in more sophisticated ways. s
Polymers Small particles
tions that generate a flow of elec-
trons, or electric current. To make a
Joaquín Rodríguez-López, 35
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN