Enhanced stability performance of nickel nanowire with 3D conducting network for planar sodium-nickel chloride batteries

High temperature sodium batteries with inorganic electrolytes are attracting increasing attention due to their high thermal stability, reliability, long-cycle life and safety. Despite the intensive investigation of Na-NiCl 2 batteries during last decades, designing a stable conducting network in the cathode is still challenging but desirable. In this work, a new cathode structure composed of Ni nanowires with an effective electron conducting network is proposed for planar sodium–nickel chloride batteries . During the first stage of charge, Ni nanowires reacted with Cl ion to form NiCl 2 on the surface and the excessive Ni nanowires inside can serve as conducting framework to facilitate the fast electron transport . As expected, the metal nanowires show a high specific capacity of 130 mA h g −1 (∼14 mAh cm −2 ) at 0.05 C after 100 cycles. Meanwhile, the batteries show stable cycling performance at 0.05 C with a high cut-off energy density of 360 W h kg −1 , much higher than the traditional tubular sodium-nickel chloride batteries (∼100 Wh kg −1 ). Scanning electron microscope (SEM) images of the cathode after long cycling reveal the ultra-slow growth of Ni particles, confirming the excellent stability of the prepared nanowires cathode.