AN IN SITU EPR STUDY OF ELECTROCHEMICALLY DOPED TRANS POLYACETYLENE

An in situ EPR study has been carried out during repeated charge/discharge cycles of a battery consisting of trans polyacetylene (PA) as the cathode and Li/Al alloy as the anode. The detected spin concentration reversibly increased by less than a factor of two and the maximum A/B ratio decreased with each repeated cycle for ClO4- in propylene carbonate and BF4- in sulfolane as the dopants. While this decreasing A/B ratio is consistent with decreasing conductivity in the doped state, the observed invariance of ESR linewidth before and after doping suggests that massive disruption of chain conjugation does not occur during battery cycling.