Alumni Relations
Faculty Highlights
Faculty Profile: Elton Cairns
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Professor Elton Cairns |
Elton Cairns has worked on battery and fuel cell technology
for almost 40 years, so it’s only natural that he drives a hybrid
car (a Toyota Prius, to be exact). He is thrilled to be motoring around
Northern California in a “green” car based on chemical principles
he helped discover.
The focus of my research is to understand at the
atomic level what features are important for high performance and long
life of both batteries and fuel cells,” he said.
Chemical engineering or chemistry?
Although he is a member of the chemical engineering department,
Cairns has straddled the thin line between chemistry and chemical engineering
throughout much of his career. He received a B.S. in each field at Michigan
Tech—as if just one degree wasn’t challenging enough. He applied
to graduate school at Berkeley based on the chemistry department’s
outstanding reputation, was accepted into the College of Chemistry and,
as a nice bonus, won the Dow Chemical Company Fellowship.
“I arrived in the college office to register and
to get my paycheck,” he noted. “That’s when I discovered
that my fellowship was intended to be for a chemical engineering student.”
The administration at first wanted him either to enroll
as a chemical engineering student or to give up the fellowship, two alternatives
that did not appeal to Cairns. “I ended up keeping the fellowship
and majoring in chemical engineering but did half of my thesis work in
chemistry, graduating in 1959. And I had the honor of being John Prausnitz’s
first graduate student,” he continued.
“After graduation I was invited to work on
the proton exchange membrane fuel cell at General Electric, eventually
helping to develop the first fuel cell system to be launched into space,
through the Gemini program,” related Cairns. “In outer space,
you need a lightweight and extremely efficient power plant, a requirement
uniquely met by fuel cells, especially since price is not a prevailing
issue.” He then moved to Argonne National Lab, where he started the
battery and fuel cell program there.
Leading LBNL
In 1978 Berkeley called with an offer for Cairns to become Associate Director at LBNL and Professor of Chemical Engineering. “It was supposed to be a five-year appointment at LBNL, but kept being extended, eventually ending in 1996, after 18 years, when I came to the chemical engineering department full-time.”
Now a professor of the graduate school in chemical engineering,
Cairns is devoted around the clock to research.
“The demand for batteries and fuel cells is continuing
to grow. People want cell phones and laptops that don’t discharge
in the middle of an important call or presentation,” he explained.
Electrode fundamentals
“We study the fundamentals of the materials for electrodes
using techniques from electrochemistry and analytical tools that are sensitive
at the atomic level.
“Most high-performance rechargeable batteries use
lithium, which moves between the positive and negative electrodes as the
battery powers a machine and is then recharged. The materials in the electrode
must be able to accommodate the lithium ions with a minimum of structural
rearrangement. Right now, the positive electrode tends to be comprised
of cobalt oxide, which is toxic, hazardous to the environment, expensive
and in short supply.
“One of the most promising alternatives to cobalt
oxide is manganese oxide (MnxOy),
which is cheap and environmentally benign. One drawback, though, is that
MnxOy batteries do not last long because the material breaks down too
quickly; Mn(+3) can disproportionate to Mn(+2) and Mn(+4),” he explained.
However, Cairns and his colleagues found that by replacing a small amount
of the manganese with another metal, such as chromium or aluminum, the
electrode is more stable and the lifetime of the battery can be greatly
extended.
“My group is investigating how the stability of MnxOy
is affected by small amounts of different metals. We are studying these
materials at the atomic level using spectroscopic techniques, including
X-ray absorption spectroscopy in collaboration with professor Stephen
Cramer of UC Davis, and NMR in collaboration with fellow chemical
engineering professor Jeffrey Reimer. We have also pioneered the
use of photothermal deflection spectroscopy for the in situ characterization
of electrochemical systems.
“Through these methods, we have demonstrated that
the greater the covalency of the chemical bonds in the metal oxide, the
more stable it is as an electrode material,” he explained.
At the other end of the battery, Cairns’s group is synthesizing and testing new materials for the negative electrode, which is usually made of flammable carbon materials. In a battery, flammable equals danger.
Additionally, the carbon electrode material is too
slow in taking up the lithium ion, which can lead to the extremely unsafe
situation of lithium metal being deposited on the electrode.
Then there are fuel cells
Fuel cells are a close relative of the battery—both
convert chemical energy to electrical energy. A lot of research directors
and politicians are currently betting that fuel cells will be an environmentally-safe
replacement for internal combustion engines in cars. “However, there
are some serious challenges that must be solved by chemical engineers
before fuel cells are ready for prime time,” said Cairns. “Fuel
cells typically operate on hydrogen, so it needs to be carried on the
vehicle in a storage tank or produced on board by a complex fuel reformer.
Hydrogen is difficult to store. Right now the storage system weighs 30-50
times the weight of the hydrogen it stores. And storing a flammable gas
at high pressure on a vehicle doesn’t seem like a good idea.”
One option is to power the fuel cell by pumping a liquid
fuel such as methanol (CH3OH) into the fuel tank
and then feeding it into a system that would catalyze its conversion into
carbon dioxide and hydrogen. That way the hydrogen would be produced in
the vehicles as needed. However, there are still some obstacles to this
technology being implemented. The carbon monoxide byproduct must be removed
safely from the system because it is a poison to the platinum catalyst
(as well as to humans). Also, the control of the reaction would need to
be precise since hydrogen should really be produced only when the car
is moving and not when the car is stopped.
“We would like to circumvent these problems by developing
an electrocatalyst that will act directly on the methanol and use very
little energy in the conversion of CH3OH to CO2 and H2 and electricity.
It would also operate under mild conditions,” he explained. So far,
platinum alloys are the most promising.
Although he is technically retired from teaching, Cairns
still loves to interact with students in the lab. “I have graduated
approximately 30 students so far. With all of them I have enjoyed the
intellectual adventure of designing the experiments and interpreting the
results.
“No two days are alike; this keeps me interested
and involved.”
