Helping to Expand the Horizon for Lithium-Ion Batteries

Chemical Engineering student expands family of composite electrode materials

Becky Ward excels in sports as well as academics. A soccer defender at McDaniel College, Ward was named to the "ESPN the Magazine" Academic All-District II First Team. Photo by David Sinclair.

Rebecca Ward joined Argonne in the summer of 2005 between her junior and senior years at McDaniel College, a liberal arts college in suburban Maryland. Becky was a double major—physics and chemistry—and had aspirations to work in the field of nuclear chemistry. She chose nuclear chemistry early on, having been strongly influenced as a freshman by seminar courses on nuclear power and waste issues.

Wanting more experience and laboratory work to help her get into graduate school, she applied for the U.S. Department of Energy's Science Undergraduate Laboratory Internships, or SULI, program. Her only other research experience was as a Research Experiences for Undergraduates (National Science Foundation) student the previous summer at Wellesley College studying Bose-Einstein condensates.

In Argonne's Chemical Engineering Division, Becky was assigned to work on two different projects within the Battery Technology Department's Materials Research Group. Initially a project on coating metallic electrodes to control surface chemistry was used to teach her the basics of cell building and electrochemical characterization. Once these techniques were mastered, she started her second project examining composites between olivine (e.g., LiFePO₄) structures and spinel (e.g., LiMn₂O₄) or layered (e.g., LiCoO₂) structures. These are the three main classes of materials used in lithium ion batteries. The battery materials group had identified a series of composite materials based on spinels and layered materials that are of significant interest to industry. Becky’s project was an attempt to expand that work to include olivine type materials.

Her approach to synthesizing the olivine materials utilized three different routes – high temperature calcination, ball-milling, and a low-temperature coating method. Even though the optimal candidate materials were used, the complexity of the reaction mixtures made it difficult to isolate the desired product. Becky persisted, however, and after further analysis, the low-temperature coating method was modified to make the desired composite materials. These materials were very stable, with good electrochemical cycling. Initial characterization of the materials showed that they are very promising.

According to Becky's supervisor, materials chemist Jack Vaughey, “Becky did a great job, in part due to her outstanding organizational skills and determination. When initial reactions didn’t go as hoped, she persisted until the problem was solved. For this olivine composite project, we still are working on the same types of materials she initially developed, but taking it in a slightly different direction to optimize the desired properties. Becky’s efforts were definitely a cornerstone of some of our future efforts.”

Becky says that in addition to the technical skills that she took away from Argonne, she learned a lot about the scientific community and enjoyed the atmosphere of a national laboratory, where everyone was focused on research and interested in collaboration. This was not her first experience in an R&D setting; she also completed an internship at the National Institute of Standards and Technology working on a dosimetry project earlier in her undergraduate studies.

DOE/SULI interns are required to submit a final report on their work projects. Typically, DOE chooses only 15 papers from the entire SULI program for publishing to its Journal of Undergraduate Research. Becky's report was one of them. As an additional honor she was awarded by DOE an all-expenses-paid trip to the 2006 American Association for the Advancement of Science (AAAS) meeting held in St Louis in February. Her poster was one of only 10 selected for display at the AAAS meeting. Becky says that she "was extremely honored to be selected from such a talented pool of students. The experience of attending the AAAS meeting was invaluable in terms of networking and developing a better understanding of scientific communication."

As for the future, Becky certainly has options. She has been accepted to five PhD programs for physical chemistry or chemical physics, and says she is leaning toward nuclear chemistry.

This work was funded by the U.S. Department of Energy, Office of Energy Efficiency and Renewable Energy, FreedomCAR and Vehicle Technologies program.

More Information

• Department of Energy's SULI Program