SciBridge: Building Scientific Connections Between Scientists in Africa and the U.S.
May 2014
Building scientific bridges: Materials researchers from Africa and the U.S.
work together to build a dye-sensitized solar cell. Learn more at www.scibridge.org.
Key Achievements
SciBridge is a direct outgrowth of the friendship formed between Veronica Augustyn (U. Texas, USA) and John Paul Eneku (Makerere University, Uganda) at the first JUAMI school in December 2012. Their focus is on enhancing materials science educational opportunities for aspiring African scientists by creating exciting experimental kits on the theme of materials for energy and sending these to African universities, with follow-up online web seminars presented by U.S. researchers. They have been awarded a special "Grassroots" grant from the Materials Research Society Foundation to put their ideas into action. Their very first SciBridge workshops were held at Makerere University from October 31 - November 1, 2014, with the follow-up webinar lecture taking place on November 6. It was a big success! Learn more at www.scibridge.org.
Significance and Impact
Research into materials for sustainable energy remains a critical topic in modern society. Building off of the collaborative spirit fostered by JUAMI, SciBridge is motivated by the desire to continue and grow the scientific discussion between U.S. and African scientists on this exciting research field. The experimental kits sent to African universities will allow students two perform one- or two-day experiments on highly relevant topics in energy-related materials science. Following the experiments, the students will have the opportunity to discuss their results and the relevant science with each other and with a U.S. researcher via an online web seminar. These experiences will both educate and excite young African materials science students, as well as enable longer-term scientific collaborations between African and U.S. researchers.
The SciBridge project is based at the University of Texas at Austin and Makerere University in Kampala, Uganda. The collaboration also involves multiple universities in the U.S. and Africa to develop as many research connections as possible.
People Involved
Veronica Augustyn
John Paul Eneku
Participants at the first SciBridge workshop at Makerere University display their working dye-sensitized solar cell.
Lithium excess cathodes studied with atomic pair distribution function analysis
April 2014
Crystal structure of a lithium-ion battery cathode, showing layered planes of
lithium ions (green) and transition metal ions (brown and gray).
Key Achievements
We are investigating the possibility of a local or partial phase change occurring in a specific cathode material when fully charged, which has significant implications for battery reversibility. This work represents a novel application of pair distribution function (PDF) methods to lithium battery materials.
Significance and Impact
A rechargeable lithium ion battery operates by reversibly cycling lithium ions between two electrodes, the anode and the cathode. The most common type of lithium ion battery cathode materials are lithium transition metal oxides, LiMO2. Reversible cycling of lithium ions from the cathode requires sufficient lithium diffusivity and an open, robust "host" structure that resists strain from the insertion and extraction of lithium ions.
During charge, lithium ions are removed from the cathode, changing the chemical composition of the cathode from LiMO2 to Li(1-x)MO2. This creates a significant number of open cation sites in the cathode when the material is fully charged, and tends to destabilize the cathode structure. One possible way for the cathode to stabilize after some fraction of lithium ions is extracted is to undergo a partial or full phase transition. This phase transition may not be reversible, and thus may have a significant impact on battery reversibility. It is the possibility of this partial or full phase transition which we are exploring in this work.
Research Details
This is a collaboration combining the battery expertise of Professor Gerbrand Ceder at MIT and the x-ray scattering expertise of Professor Simon Billinge at Columbia to study local structural changes in lithium ion battery cathode materials. We are performing temperature dependent, in-situ synchrotron x-ray experiments with PDF analysis to track structural changes in these materials.
People Involved
Nancy Twu (MIT)
Chenyang Shi (Columbia)
Simon Billinge (Columbia)
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