A study of Ni3S2 synthesized by mechanical alloying for Na/Ni3S2 cell

To synthesize nanocrystalline Ni3S2 cathode material for Na/Ni3S2 cell with low cost nickel and sulfur elements, mechanical alloying (MA) was employed directly and with different ball powder ratios (BPRs) of 20:1, 25:1 and 30:1, the mean particle size of 3.99, 2.84 and 2.75 mu m can be obtained, respectively. In order to ulteriorly reduce the particle size to improve the contact areas between the active materials, the wet ball milling with the normal Hexane (C6H14) as the milling solvent was also conducted for 30 h using the ball milling machine, and the submicro Ni3S2 powder particles can be gained. The charge/discharge properties of Na/Ni3S2 cells for wet milled system were investigated at room temperature using 1 M NaCF3SO3 (sodium trifluoromethanesulfonate) dissolved in TEGDME (tetra ethylene glycol dimethyl ether) as the liquid electrolyte. And the initial charge/discharge capacity was 397 and 425 mAh/g, respectively, which indicates the small particle size of cathode materials are conductive to the discharge properties.