Redox behaviors of the poly(2,5-dihydroxy-1,4-benzoquinone-3,6-methylene) (PDBM)-coated electrodes composited with carbon black (CB) or poly(3,4-ethylenedioxy-thiophene) (PEDOT) are presented. Effects of PEDOT additive on the redox activity of PDBM were investigated to apply their composite materials as candidates of cathodes for rechargeable lithium batteries. The film having a PEDOT/PDBM with weight ratio of 1/1 shows a gravimetric capacity of 129mAhg−1 (corresponding to 188mAhg−1 for PDBM and 70mAhg−1 for PEDOT). The highest energy density observed was 140mAhg−1 (406mWhg−1) for the composite cathode. Good cycle-ability over 100 cycles was attained with a PEDOT/PDBM composite cathode.