报告人：段镶锋 教授 (Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095, USA)
报告题目：Tailoring Charge Transport for Highly Efficient Electrochemical Energy Conversion and Storage
Supercapacitors, batteries and fuel cells represent three distinct electrochemical energy conversion devices of increasing importance for applications in mobile electronics, electric vehicles, and renewable energy industry. A common feature of these devices involves coupled ion transport (and storage) and electron transport in active electrode materials. Tremendous research efforts have been devoted to developing new electrode materials (e.g., silicon and niobia) with the potential to enable far higher energy or power density than those of today’s devices. However, these new materials have thus far failed to deliver their promise in practical devices because the exceptional performance is typically only achievable in ultrathin electrodes with very low mass loadings (< 1 mg cm-2) and cannot be easily scaled into devices with practical levels of mass loading (>10 mg cm-2). To sustain the same electrochemical performance in practical electrodes with higher mass loading requires the delivery of proportionally more charge (electrons and ions) across a proportionally longer distance, which represents a formidable challenge largely overlooked to date. In this talk, I will discuss the critical role of charge transport in electrochemical devices and give a few examples how the performance of various electrochemical devices can be dramatically improved by tailoring the charge transport process. In particular, I will describe the design of a three-dimensional holey graphene framework simultaneously with excellent electron and ion transport properties, to enable a series of supercapacitor or battery electrodes with unprecedented combination of energy and power density at high mass loading (10-20 mg cm-2), marking a critical step towards realizing the potential of these materials in practical devices. Lastly, I will briefly discuss a unique design of one-dimensional platinum nanowire electrocatalysts with much more efficient charge transfer from the catalytic active sites to the current collector to greatly enhance their performance as highly efficient fuel cell catalysts.
Dr. Duan received his B.S. Degree from University of Science and Technology of China in 1997, and Ph.D. degree from Harvard University in 2002. He was a Founding Scientist and then Manager of Advanced Technology at Nanosys Inc., a nanotechnology startup founded based partly on his doctoral research. Dr. Duan joined UCLA with a Howard Reiss Career Development Chair in 2008, and was promoted to Associate Professor in 2012 and Full Professor in 2013. Dr. Duan’s research interest includes nanoscale materials, devices and their applications in future electronic, energy and health technologies. A strong emphasis is placed on the hetero-integration of multi-composition, multi-structure and multi-function at the nanoscale, and by doing so, creating a new generation of integrated nanosystems with unprecedented performance or unique functions to break the boundaries of traditional technologies. Dr. Duan has published over 200 papers with over 30,000 citations, and holds over 40 issued US patents. For his pioneer research in nanoscale science and technology, Dr. Duan has received many awards, including MIT Technology Review Top-100 Innovator Award, NIH Director’s New Innovator Award, NSF Career Award, Alpha Chi Sigma Glen T. Seaborg Award, Herbert Newby McCoy Research Award, US Presidential Early Career Award for Scientists and Engineers (PECASE), ONR Young Investigator Award, DOE Early Career Scientist Award, Human Frontier Science Program Young Investigator Award, Dupont Young Professor, Journal of Materials Chemistry Lectureship, International Union of Materials Research Society and Singapore Materials Research Society Young Researcher Award, the Beilby Medal and Prize, the Nano Korea Award, and most recently International Society of Electrochemistry Zhao-Wu Tian Prize for Energy Electrochemistry.