Finding and optimizing the appropriate cathode materials in the electrolyte are critical to the development of chloride ion batteries. Herein, chloride ion-doped polyaniline/carbon nanotubes (PANI/CNTs) composite materials, which were prepared by an in situ chemical oxidative polymerization method using FeCl3 center dot 6H(2)O as the oxidant, have been developed as new cathodes for chloride ion battery. The PANI/CNTs cathode showed reversible electrochemical energy storage through redox reactions of nitrogen species and chloride ion transfer, as confirmed by the results of the electrochemical testing and X-ray photoelectron spectroscopy. The structural configuration of PANI by the incorporation of conductive CNT carrier contributed to significant improvement in the electrochemical properties. More than 80 mAh g(-1) stable capacity and a high Coulombic efficiency of about 99% were delivered. This work offers a promising strategy for designing chloride ion storage electrode and novel electrochemical systems. (c) 2018 Elsevier Ltd. All rights reserved.