HIGH ENERGY DENSITY SILICON ANODES FOR LITHIUM-ION BATTERIES: COMBINING HOLLOW NANOSPHERES WITH CONDUCTIVE POLYMER BINDER

摘要

High energy density batteries with long cycle life are critical for various energy storage applications. Alloying electrodes, such as silicon, react with lithium at low potential and offer much greater theoretical specific capacity than graphite. nThe alloying reaction of Si with lithium, however, causes significant volume expansion during lithiation process and lead to the fracture of Si particles because of huge lithiation-induced mechanical stress. Various approaches with different focus, such as nanoengieering Si anode structures1, stabilizing solid-electrolyte interphases between Si and organic electrolyte2, and synthesizing new polymer binders to accommodate the volume change3,4, have been shown successfully improving the energy density and cycle life, bringing Si anodes one step closer into practical Li-ion batteries. In this preprint, we show that both the active hollow nanospheres Si anode structure and the inactive conductive polymer binder have significant impact on the anode cycling performance. Combining the hollow nanospheres with conductive polymer binder, long cycle life Si anode is demonstrated at high energy density.