STRUCTURAL AND ELECTROCHEMICAL PROPERTIES OF LITHIATED POLYMERIZED AROMATICS - ANODES FOR LITHIUM-ION CELLS

Structural and electrochemical properties of lithiated polymerized aromatics as anodes for lithium-ion cells have been studied using 3,4,9,10-perylenetetra-3,4,9,10-carboxylic dianhydride (PTCDA) heated at 550-1000 degrees C in inert gas. Lithium can be reversibly doped in PTCDA heated at 550 degrees C with the largest specific capacity of 660 mA h g(-1) between 0 and 2 V vs Li/Li+. The capacity of the pyrolyzed PTCDA decreased with increasing heat-treatment temperature (HTT). IR and XRD measurements revealed that the structure of pyrolyzed PTCDA shifted from a polymerized perylene to a disordered carbon composed of small graphite layers with increasing HTT. The IR spectra of lithiated pyrolyzed PTCDA suggested that the reversible lithium doping in the pyrolyzed PTCDA heated at temperatures of less than 650 degrees C was attributed to an ionic complex composed of lithium ions and aromatic rings with negative charges. The relationship between the lithium-doping mechanism and the structure of the pyrolyzed PTCDA has been discussed.