The discharge properties of Na/Ni3S2 cell at ambient temperature

The discharge properties of a Na/Ni3S2 cell using 1 M NaCF3SO3 in tetra(ethylene glycol)dimethyl ether liquid electrolyte were investigated at room temperature. The products were characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. Electrochemical properties of Na/Ni3S2 cells were also presented by cyclic voltammetry and the galvanostatic current method. Na/Ni3S2 cells have an initial discharge capacity of 420 mAh g−1 with a plateau potential at 0.94 V versus Na/Na+. After the first discharge, Ni3S2 and Na react at room temperature and then form sodium sulfide (Na2S) and nickel. Sodium ion can be partially deintercalated from Na2S charge reaction. The discharge process can be explained as follows: Ni3S2 + 4Na ↔ 3Ni + 2Na2S.