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A D V A N C E D M A T E R I A L S & P R O C E S S E S | F E B R U A R Y / M A R C H 2 0 1 7
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A BATTERY OF CELLS
Researchers at Binghamton Uni-
versity, State University of New York
created a bacteria-powered battery on
a single sheet of paper. On one half of
the piece of chromatography paper, a
ribbon of silver nitrate underneath a
thin layer of wax serves as a cathode.
On the other half, a reservoir made of
a conductive polymer serves as the
anode. Once the sheet is properly fold-
ed, a few drops of bacteria-filled liquid
are added, and the microbes’ cellular
respiration powers the battery. Tests
show that different folding and stacking
methods can alter the output: Six bat-
teries in three parallel series generate
31.51 µW at 125.53 µA, and a 6x6 config-
uration produces 44.85 µW at 105.89 µA.
“Microorganisms can harvest
electrical power from any type of
biodegradable source, like wastewater,
that is readily available,” explains assis-
tant professor Seokheun Choi. Because
of this, bio-batteries could serve as a
choice power source for disposable,
point-of-care diagnostic sensors in re-
mote areas. While it would take millions
of paper batteries to illuminate a 40-W
light bulb, the cells are strong enough
to power lifesaving glucose monitor-
ing or pathogen detection diagnostics.
CAPTURING ENERGY WITH A
WAVE OF THE HAND
Engineers at Penn State, State Col-
lege, Pa., designed a transducer that
could be used to harvest low-frequency,
mechanical energy from environmental
sources—such as wind, ocean waves,
and human motion—and use it to power
next-generation electronics. While de-
vices that convert ambient mechanical
energy into electricity are widely used
today, most depend on the piezoelec-
tric effect and are only efficient above
10 Hz. The new device—a flexible, or-
ganic, ionic diode—has a peak power
density at least as great as an optimal-
ly performing piezoelectric generator,
but at a frequency of only 0.1 Hz. “Right
now, at low frequencies, no other device
can outperform this one,” asserts Qing
Wang, professor of materials science
and engineering.
BRIEF
As part of the Manufacturing USA initiative, the DOE announced its Reducing Embodied-energy and Decreasing
Emissions (REMADE) Institute. The new organization, led by the Sustainable Manufacturing Innovation Alliance
(Rochester, N.Y.), will leverage up to $70 million in federal funding plus $70 million in matching cost-share commit-
ments frommore than 100 private partners. Charged with slashing the cost of technologies needed to reuse, recycle,
and remanufacture materials such as metals, fibers, polymers, and electronic waste, REMADE is aiming for a 50%
improvement in overall energy efficiency by 2027. energy.gov.
ENERGY TRENDS
Researchers created a bacteria-powered
battery on a single sheet of paper that
can power disposable electronics. Cour-
tesy of Seokheun.
The new ionic diode is composed
of two nanocomposite electrodes with
oppositely charged mobile ions separat-
ed by a polycarbonate membrane. The
electrodes are comprised of a polymeric
matrix filled with carbon nanotubes—to
enhance conductivity and mechanical
strength—and infused with ionic liquids.
When mechanical force is applied, ions
diffuse across the membrane, creating a
continuous direct current, while a built-
in potential that opposes ion diffusion is
established until equilibrium is reached.
The flexible, lightweight polymer de-
vice could be incorporated into a smart
phone, for example, where it could cap-
ture the energy used to touch the screen
and use it to replenish up to 40% of the
battery’s capacity
Energy-harvesting PN junction. Courtesy
of Qing Wang, Penn State.