In this manuscript, it is reported how the microstructure of metal composites can be designed to obtain excellent cycle performance in Na-(Ni,Fe)Cl-2 battery. The microstructure consists of an active material and a conducting material. The conducting material is an active material as well as a conducting chain (an electron path). In Na-(Ni,Fe)Cl-2 cells, it is preferable that Ni is selected as the conducting material, since the nickel chloride is not formed on the surface of Ni particles during the electrochemical reaction of Fe particles. In addition, the particle size of Ni should be smaller than that of Fe, in order to ensure that the conducting chain is well-connected. Through this design, the cycle performance of a Na-(Ni,Fe)Cl-2 cell was significantly improved, compared to that of a Na-NiCl2 cell. At the 100th cycle, the charge/discharge capacity of a Na-(Ni,Fe)Cl-2 cell was much higher than that of a Na-NiCl2 cell, approximately 42%. (C) 2016 Elsevier B.V. All rights reserved.