Poly(3,4-ethylenedioxythiophene) (PEDOT) was chemically synthesized and characterized by FT-IR, XRD, XPS, TGA and organic elemental analysis (EA). The polymer was tested as cathode active material for rechargeable lithium batteries. The cyclic voltammetry (CV) and charge-discharge tests of PEDOT as the cathode active material was investigated in an electrolyte system of LiN(CF3SO2)(2)/1,2-dimethoxyethane/1,3-dioxopentane (1:2 by weight). The peak discharge capacity of up to 691 mAh/g was obtained during the 1st cycle, and remained above 330 mAh/g after 44 cycles. These results indicate that PEDOT can afford a high specific capacity as a cathode active material. A redox mechanism is tentatively proposed. (c) 2008 Elsevier Ltd. All rights reserved.