Introduction / Background
EEC-1132648 Summer Research Project:
C.S.Peterson; M.P.Yeager; W.Du.; X.Teng
The Joan and James Lietzel Center for
Science, Technology, Engineering and Math
Education: Research Experience for
Teachers in Engineering Program 2012
Topic: METAL OXIDE NANAOSTRUCTURES AS FARADIAC REDOX
REACTIONS FOR ENERGY STORAGE APPLICATIONS OPTIONS WITH
POWER AND ENERGY DENSITIES BETWEEN BATTERIES AND CAPACITORS:
Goal: Can a coating of polypyrrole on nanoparticle Mn3O4 metal oxide be
prepared by in-situ polymerization to improve the specific capacitance
of by reducing charge-transfer resistance over the
Electrochemical capacitors (EC) store energy in an electric field
that can be charged and discharged rapidly. These
electrochemical capacitors are useful in combination with
conventional batteries in providing electrical energy storage and
release where rapid high power delivery or uptake is needed.
Though small single cell low voltage EC have been commercially
available, different applications require improved energy density.
Psuedo-capacitors or redox-supercapacitors (SCs) are a class of
the EC energy storage device that fill the gap between batteries
with high energy densities and electrostatic capacitors with high
power densities. These redox-capacitors rely on metal oxides
nanomaterials which undergo fast and reversible surface reactions
for charge storage. Emerging energy applications for EC/SC with
characteristics of high power and improved energy densities has
prompted research into materials for electrodes in EC/SCs. These
materials should be low cost, low toxicity, have large specific
capacitance and long life cycle based on to their potential for multi-
electron transfer during Faradaic reactions.
This is an investigation to enhance the conductivity of the redox
reaction by reducing the distance traveled to between the metal
oxide and the electrode through creating a nanometer thickness
layer of polypyrrole conductive polymer on the metal oxide through
To facilitate charge transfer of Faradaic redox reaction of :
Mn+2--> Mn+3 + e-
conductive polymer, polypyrrole, PPy, was formed from the
monomer in-situ with nanoparticle metal oxide.
Compared cyclic voltagrammetric specific capacitance
*100/ % Mn3O4 (+ 20% PTFE non-conductive)
*50/50 % in-situ polymerizered pyrrole / Mn3O4
*90/10 % in-situ polymerizered pyrrole / Mn3O4
*100 % polymerizered pyrrole
In-situ polymerization of pyrrole on metal oxide nanoparticles for pseudo capacitors.
Synthesis: Nanoparticle Metal Oxide Mn3O4
7/12 syn /50% by weight PPy 1 to 10 Mn3O4to PPy:
7/12 syn with 10% /90% by weight PPy
50/50 % by weight Ppy/Mn3O4:
90/10 % by weight Ppy/Mn3O4
The optimization of electrode materials are critical for further
development. Increasing the surface area through synthesis of
nanometer size particles increase surface reactions. How these metal
oxides are adhered to the electrode may play a significant role in their
effectiveness. Though there is ongoing research of the choice of metal
oxide for redox reaction, reducing the resistivity to the electron charge
transfer to the electrode from the Faradaic redox reaction may enhance
the specific capacitance and charge / discharge cycle endurance of the
Cat Peterson is an in-service high school teacher in Naugatuck, CT. Prior to teaching, she earned a B.S. in Chemistry from the University of
Connecticut and enjoyed ten years of S.T.E.M. careers, holding jobs as application chemist, quality director, product/ project manager and program
launch leader for a variety of engineered polymer composite manufacturers. Cat then became certified in 7-12 grade Chemistry and General
Science, and teaches Academic and Honors chemistry to sophomores and juniors along with diverse science electives. After earning her M.S. in
Chemistry from Saint Joseph College in 2009, she had been reenergized in promoting S.T.E.M. education and career awareness. This opportunity
to conduct summer research in a S.T.E.M. area through the National Science Foundation grant awarded to the James and Joan Lietzel Center at
the University of New Hampshire, Durham, NH. has empowered her to encourage, excite and teach students to appreciate science, math,
technology and engineering.
The Mn3O4 metal oxide was synthesized per a
method devised by Matt P. Yeager et al. The
material was centrifuged, vacuum dried and
massed to allow for nown ratio of metal oxide to
polymer. Verification of particle size of 15-20 nm
by TEM magnification 40000 times is shown below:
Prepared dilute solution MnCl2
10 mL of DIDW H2O
Prepared 0.300 M KOH:
10 mL of DIDW H2O
163 mg KOH
Placed in Syringe Pump
Added dropwise with programmable syringe pump at rate of
0.167 ml per minute for 50 minutes. 145 mg KOH / 8.33 mL
used. Allowed 30 additional minutes stirring to react. Used four
centrifuge tubes. Centrifuged for 10 minutes: clear supernatant.
Decanted and consolidated to two tubes. Filled with DI H2O for
wash and centrifuged for 10 minutes. Decanted and
consolidated to one tube. Filled with ethanol and centrifuged 10
minutes. Decanted and vacuum dried at room temp for 16
hours. TEM sample prepared on carbon support .
Half Cell Results
Hope to get some actual CVs this week
and calculate Specific Capacitance for
plain glassy carbon electron and four
samples listed above
Report in Farads per gram
Compare to other 650 F g-1 etc.
A sample of Mn3O4 from synthesis, mass of 10.2 mg was diluted with 4.450
mL to a 0.010M aqueous solution which was sonicated for 10 minutes prior to
and 10 additional minutes after adding 105 µL of a 10% pyrrole monomer
dissolved in ethanol. To initiate polymerization 105 µL of 0.010M aqueous
Fe(NO3)3 was added, followed by 30 minutes of sonication. The sample was
centrifuged and dried. A small dimension particles appeared to settle.
A similar method was used in the preparation of the 9 to 1 sample pyrrole /
M3O4, using 9 times the amount of pyrrole and Fe (NO3)3. The particle size
that settled was noticeably larger and descended at an increased rate.
50/50 % in-situ polymerizered
pyrrole / Mn3O4
90/10 % in-situ polymerizered
pyrrole / Mn3O4
TEM images were taken from samples
that had been oven dried and then
redissolved in ethanol, prepared on
carbon supported copper wire screens.
TEM images are at 40000 times magnification.
The 15-20 nm octahedral shape Mn3O4 particles
can still be vsualized though the particles appear to be
clumped together in 100-300 nm structures, The
lighter gray, more evident in the 90/10, is assumed to
be the polypyrrole compound.
•Comparision to other ratios of Ppy/Mn3O4 for
optimization or other conductive polymers.
•SEM determination of individual particle size Even
if the PPy / Mn3O4 are not clearly distinct
individually coated particles, the aggregate particle
size appears to be less than 1000 nm and have a
high surface area structure.
• UNH Department of Chemical Engineering
• Xaiowei Teng, Wenxin Du, Matthew P. Yeager for encouraging me to undertake a unique direction utilizing their
resources which allowed me to pursue a distinct research project and enduring my unending questions
• Matthew Sullivan and Dom Montollo for coaching with laboratory synthesis and testing procedures.
• Carole Lessard, Katie Stella, Baron Richardson, Michelle Kelly, Berkley Sadona and April Cartwright for their
camaraderie, inspiration, and sharing of their instructional experiences in a professional development mode.
• Nancy Cherim, at UNH-UIC for access, training and assistance in TEM photography.
• Stephen R. Hale, at the Lietzel Center for coordinating the RETE program and providing well- defined direction,
appropriate resources, confident leadership and encouragement throughout this experience.
Mass on electrode of 5 micrograms total; therefore Mn3O4 loading was reduced while Ppy was increased