STRUCTURE AND PROPERTIES OF DEEPLY LI-DOPED POLYACENIC SEMICONDUCTOR-MATERIALS BEYOND C6LI STAGE

The structure and properties of deeply Li-doped polyacenic semiconductor (PAS) materials have been investigated in association with their utilization as electrodes in rechargeable batteries. The doped lithium was found neither in metallic nor in ionic states even in the most deeply doped state (C2.2Li stage) by X-ray photoelectron spectroscopy (XPS) measurements. It has also been confirmed that the PAS electrode has a large capacity (530 mA h/g) with good stability and reversibility. These results strongly suggest that the PAS can make an excellent anode material for secondary batteries. Finally, we discuss that the PAS doped up to the C2Li stage can exhibit an energy density per volume as high as lithium metal.