A LiMnO2–PAn–DMcT composite cathode for a lithium polymer battery (LPB) was developed. We investigated impedance spectroscopy, electrochemical properties of LiMnO2, LiMnO2–PAn and LiMnO2–PAn–DMcT composites with polyvinylidene (PVDF)-based polymer electrolyte as a function of mixing ratio. The capacity of LiMnO2 with 3wt.% PAn–12wt.% SP270 was higher than that of LiMnO2 with 15wt.% SP270. The discharge capacity of LiMnO2–PAn with 3wt.% PPy was 119 and 121mAh/g at 7 and 15 cycles. The capacity of LiMnO2 with 2wt.% PAn and 3wt.% DMcT was higher than that of LiMnO2 with 3wt.% PAn and 12wt.% SP270 with cycling. The LiMnO2–PAn–DMcT composite cathode with 2wt.% PAn and 3wt.% DMcT in PVDF-based electrolyte shows good capacity with cycling.