Fiber-type cathodes composed of Na-Mn-O for use in a sodium ion battery were developed. The active material was synthesized onto carbon fibers by a two-step procedure that included electrodeposition and hydrothermal reactions. The active material shapes were changed depending on the experimental conditions. The scale-shaped material composed of the Na0.91MnO2 phase was formed by the electrodeposition in an Mn(NO3)(2) solution, while the circular-shaped one was obtained in the MnSO4 solution. The addition of H2O2 and increase in the hydrothermal temperature helped to decrease, the unreacted precursor phase. The scale-shaped cathode mainly composed of the Na0.91MnO2 phase exhibited the highest 185 mAh/g discharge capacity among the fiber-type Na-Mn-O electrodes,, indicating that this active material is beneficial for the intercalation and deintercalation of sodium ions:In addition, both the scale-shaped and string-shaped cathodes exhibited similar rate and cycling performances. (C) 2014 The Electrochemical Society. All rights reserved: