Li-S batteries are the most promising high energy density batteries for transportation and large-scale grid energy storage applications in the near future. Most of the reported activities on Li-S batteries rely on the fabrication of porous carbons as cathode materials. However, very limited work has been conducted to construct cathodes with defined shape via a wet chemical route, which is simple and scalable, and may thus present the favorable route toward cost-effective large scale production of cathode materials for Li-S batteries. Novel hybrid nanostructures based on sulfur nanocomposites and novel, efficient, scalable synthesis approaches are being designed in the Institute Soft Matter and Functional Materials. We study the detailed morphology and composition of the nanocomposites to understand the relationship between the porous/hollow structure and the electrochemical performance using synchrotron-based characterization techniques such as PEEM and SAX/ASAXS. Degradation mechanisms in such batteries are often connected with chemical reaction through paramagnetic states. We are currently setting up a novel 3D-spatially resolved EPR detection facility within the HEMF platform to unravel the detailed degradation mechanism on a nanoscopic level.
Materials for Hydrogen Storage
Nanocrystal-polymer hybrid systems have been developed at the Molecular Foundry in Berkeley that allow hydrogen storage because the organic polymer is transparent for hydrogen but not for oxygen. Nanoscale metals provide rapid hydrogen storage kinetics in comparison to their bulk counterparts. Their integration into polymer hybrids results in robust and high-density hydrogen cycling. In our research we apply advanced synchrotron-based analytics such as anomalous small angle X-ray scattering (ASAXS) to study particle size and distribution and shell size as a function of hydrogen load and metal nanoparticle composition.