Jiangyu Li is Professor of Mechanical Engineering at the University of Washington. His research focuses on the physical behaviors of materials. His group is developing hierarchical nanostructured materials with designed size, morphology and distribution of microstructural features for high efficiency energy harvesting and storage. The current focus is on hierarchical nanofibers using electrospinning, with immediate application to nanocrystalline thermoelectric oxides with substantially enhanced thermoelectric figure of merit. The hybrid porous nanofibers also have great potential in lithium ion batteries and solar cells.