Supercharging Future Mobility: Tailoring Charge Transport for Highly Efficient Electrochemical Energy Conversion and Storage

Seminar | February 2 | 4-5 p.m. | 120 Latimer Hall

 Xiangfeng Duan, Department of Chemistry and Biochemistry, UCLA

 College of Chemistry

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 greatly 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 supercapacitor or battery electrodes with unprecedented combination of energy and power density at high mass loading, 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.

 Light refreshments will be served at 3:50 at The Coffee Lab, 510-643-0572