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New York City Research Initiative

Research Projects at Hunter College

Go to projects in: 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004

Hunter College — 2010

7Li MAS-NMR Investigation of MnO2 Infused Carbon Nanofoam Supercapacitor Materials
Team Members

Principle Investigators (PI):
Prof. Steven G. Greenbaum
Dr. Phil Stallworth

Team Members:
Christian Mejia, Undergraduate Student
Jovi Rodriguez, High School Student

Final Research Presentation
Summary

Abstract: Recently, with the increase of environmental awareness, scientists as well as major consumer product companies are performing research to find an efficient and inexpensive way to power numerous electronics as well as vehicles. One of the major accomplishments achieved by the research done is the electrochemical double-layer capacitor also known as supercapacitors. These have many advantages and therefore many applications. Some characteristics that make supercapacitors superior power sources are long cycle life (>100,000 cycles), their manufacture and function are simple; they charge in a short amount of time, they have a high power density and are rather safe.

An important application is supercapacitors are their use in conjunction with batteries for the use in electric hybrid vehicles. The supercapacitor plays a very significant in electric hybrid vehicles due to its ability to charge and deliver energy quickly.

Hunter College — 2009

7Li MAS-NMR Investigation of MnO2 Infused Carbon Nanofoam Supercapacitors
Team Members

Principle Investigator (PI):
Prof. Steven G. Greenbaum

Mentor:
Dr. Phillip E. Stallworth

Researchers:
Chrstian Mejia, High School Student

Final Research Presentation
Summary

Abstract: MnO2 infused carbon nanofoams were investigated via MAS-NMR. This material is the component responsible for the electrical properties of electrolytic double layer capacitors (DLC), also known as supercapacitors. This is a technology that can be very useful in the power system of a car. The goal of the experiments was to identify the different lithium sites within the caron nanofoams. There are two dfinite sites: surface lithium and structural intercalated lithium. The NMR data shows the two sites, one arising at 0 ppm and 720 ppm, and a possible third site at 490 ppm. This project was worked on in conjunction with the Naval Research Lab, who is running various electrical characterization experiments.

Hunter College — 2008

High Pressure NMR Studies of Lithium-Ion Batteries & Fuel Cell Membranes
Team Members

Principle Investigator (PI):
Dr. Steve G. Greenbaum

Team Members:
Dr. Christoph Weise

Jaime Farrington, Graduate Student
Richner Erisnor, High School Teacher
Christian Mejia, High School Student

Final Research Presentation
Summary

Lithium ion batteries and hydrogen fuel cells represent two very important and still emerging energy technologies for applications in transportation and aerospace. A key component in both of these devices is the electrolyte membrane which transports the ions between the electrodes. Ionic liquids are a new class of materials with desirable properties such as high ionic conductivity, chemical and thermal stability. New membranes incorporating ionic liquids into a polymer matrix are now being evaluated for battery and fuel cell applications.

Hunter College — 2007

NMR Studies of Polymer — Silica Nanoparticle Composites
Team Members

Principle Investigator (PI):
Dr. Steve G. Greenbaum

Team Members:
Christoph F. Weise, Undergraduate Student
Shane E. Harton, Undergraduate Student
Christian Mejia, High School Student

Final Research Presentation
Summary

Throughout the years, polymer nanocomposites have shown great technological potential. These polymer nanocomposites are of great interest because of the ability of added nanoparticles to enhance the mechanical properties of polymers when mixed with them. These enhanced materials have a wide range of applications, from being used in airplane wings and automobile parts to being the new materials used in prosthetic implants. By studying nanoparticles, today's materials could be further improved and developed into more efficient systems and sophisticated technologies.

Hunter College — 2006

NMR Study of Lithium-Ion Electrode Materials
Team Members

Principle Investigator (PI):
Dr. Steve Greenbaum

Mentor(s):
George Bennett, CUNY Doctoral Student
Ameesh Khalfan, CUNY Doctoral Student

Researcher:
Christina Zayas, SHARP Apprentice

Final Research Presentation
Summary

Due to the varying environmental conditions that are present in space, batteries powering spacecrafts need to possess the ability to withstand variable temperatures. In addition, such batteries demand an increased cycle life at low depths of discharge while also requiring mechanical durability and compactness. Nuclear magnetic resonance (NMR) spectroscopy can shed light on a material at the atomic and molecular level. Through the use of a superconducting magnet and the application of electromagnetic radiation, we can learn of the structural properties of a given substance, i.e. a battery electrode. The structural quantities of interest in our study include relaxation times and the characterization of local environments of nuclei. The Jet Propulsion Laboratory (JPL) supplied the materials investigated and the nuclei probed were 7Li and 19F.

Conclusion: By using NMR spectroscopy to identify the breakdown particles which inhibit the proper functioning of Li-ion batteries, we have concluded that the electrode additives have in fact changed the structural characteristics of the spectrum. Future experimentation will be pursued to further characterize electrode additives and their behavior under different temperatures and chemical conditions. Future experiments include but are not limited to the continuation in the variation of electrode additives and concentrations to help improve their behavior in various temperatures and surface chemistries.

Ferromagnetic Resonance Study of Cobalt Nanowires for Magnetic Storage
Team Members

Principle Investigator (PI):
Dr. Steve Greenbaum

Co-Principle Investigator (Co-PI):
Dr. John Flowers, Medgar Evers College

Researchers:
Kevin Jagdipsingh, SHARP Apprentice

Final Research Presentation
Summary

The X-Band Bridge Bruker EMX spectrometer was used in the experiment to obtain the various characteristics of cobalt nanowires, such as the gyro magnetic ratio and the resonant magnetic field at various angles. It was discovered that the resonance frequency of the cobalt samples is angular dependent and peaks at around 90 degrees.

Conclusion: It was found that the cobalt samples were highly anisotropic as predicted. This is due to the ferromagnetic electron environment of the cobalt wafers.

Possible follow up research could include a repeat of the experiment using a two degree intervals on the goniometer to test the reproducibility of the experiment. Also, the cobalt sample can be tested with liquid nitrogen to see the effects of low temperature on the magnetic resonance. Another experiment would be to try orienting the wafer a different way inside of the cavity in order to see the magnetic properties of the sides not tested.

Hunter College — 2005

Magnetic Resonance Studies of Polymers for Advanced Power Sources
Team Members

Principle Investigator (Co-PI):
Dr. Steve Greenbaum

Co-Principle Investigator (Co-PI):
Dr. John Flowers, Medgar Evers College

Researchers:
Dr. Phillip Stallworth, Mentor

John Sangobowale, SHARP Apprentice

Final Research Presentations
Summary

This project involves the study lithium transition metal oxides using Electron Paramagnetic Resonance Spectroscopy (EPR). The research is carried out in the laboratory of Dr. Steve Greenbaum Professor of Physics at Hunter College. These studies are part of a larger effort, including Nuclear Magnetic Resonance (NMR)studies, to understand materials which show promise as lithium-ion battery cathodes. Major advances in lihtium battery technology would have considerable impact on the electronics industry. The much more environmentally benign lithium batteries could replace the environmentally unfriendly Ni-Cd batteries. Computer science students are assisting in writing code and data archiving and the chemistry and environmental science students operate the EPR spectrometer and collect and analyze the data obtained.

Hunter College — 2004 (continued in 2005)

High Pressure: Study of Proton Movement in a Polymer
Team Members

Principle Investigator (PI):
Dr. Steve Greenbaum

Researchers:
Professor Dr. Stanley Bajue (2004)

Nicole Leifer, CUNY Doctoral Student (2005)

George Bennett, Graduate Student (2004)

Pedro Rojas, Undergraduate Student (2004)

Christina Zayas, SHARP Apprentice (2005)
Rahsaan Bascombe, SHARP Apprentice (2004)

2005 Final Research Presentation
2004 Final Research Presentation
Summary

Use of solid-state nuclear magnetic resonance (NMR) to study the structure and dynamical properties of membranes that are being developed for advanced power sources, such as hydrogen and methanol fuel cells, and lithium batteries. Collaborators provide materials to us from universities and national labs (e.g. the NASA Jet Propulsion Laboratory), and the NMR measurements are performed at Hunter College.

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