| One of the greatest technological success stories in recent years has been that of the development and commercialization of the Li-ion battery (LIB) technology. It has been predicted that the silicon anode technology will be the next evolution in LIBs, due to its potential to enable cheaper, higher capacity batteries. To attain its immense storage capacity, the silicon particles in the anode must expand to accommodate the lithium ions. In this expansion lies the technological challenge facing further development of silicon anode technology. The consequences of the expansion can be simplified into the following issues: swelling and rupture, loss of mechanical stability due to pulverization of the electrode, and cell drying. In this thesis work, we have designed a novel nanostructured anode material that will address some of the key issues preventing commercial applicability of silicon anode. We have also designed a novel nanostructured cathode material that will store high percentage of sulfur and exhibit high capacity retention. While the synthesis of these novel nanostructured materials was the primary objective, some preliminary electrochemical data have also been presented in the thesis. These two materials (lithiated silicon as the anode and sulfur as the cathode) can be combined to construct lithium-sulfur batteries (LSBs), which have potential to provide 3-5 times more energy than that of current LIBs at lower cost. Moreover, sulfur is environmentally benign and one of the most abundant elements on earth. More importantly, its low operating voltage of 2.1 V could offer safety advantages over high-voltage intercalation cathodes (>4 V) used in LIBs. Thus, realization of a practical Li-S technology can move the U.S. rapidly toward a more sustainable transportation future. |
