Electrochemical characteristics of cathode materials NiS2 and Fe-doped NiS2 synthesized by mechanical alloying for lithium-ion batteries

In this study, fine cathode materials NiS2 and Fe-doped NiS2 are prepared by mechanical alloying (MA), small mean particle sizes of each other are obtained through wet ball-milling. To compare the performance of Li/NiS2 and Li/Fe-doped NiS2 cells prepared by both Planetary Ball Mill (PBM) and SPEX Mill (SM) respectively, the following results have been revealed: SM can do a great deal towards improving the initial discharge capacity of both cells; the cycle life of all cells prepared by PBM was better than SM which is may be due to the small number of lattice defects and low internal stress for different milling conditions used; wet milling process can help to improve the whole characteristic of Li/Fe-doped NiS2 cells, but not seem to apply to Li/NiS2 one; the main factor influencing the performance of Li-ion cells is the doping of iron elements, which may stable the crystal structure in the process of intercalation and deintercalation of lithium ions between the active materials.

Active materials of NiS2 and Fe-doped NiS2 are prepared by mechanical alloying (MA) and wet milling. Cathodes in Li/NiS2 and Li/Fe-doped NiS2 cells were both prepared by Planetary Ball Mill (PBM) and SPEX Mill (SM), showing that SM can help to improve discharge capacities of both cells, wet milling can improve the characteristic of Li/Fe-doped NiS2, but not Li/NiS2.Figure optionsDownload as PowerPoint slideHighlights
► MA is successfully applied to synthesize fine NiS2 and Fe-doped NiS2 compounds.
► SM can be of great help in improving the initial discharge capacity.
► The cells prepared by SM display relatively poor cycle properties.
► Wet milling process is helpful in decreasing the mean particle size.
► Wet milled powders can improve the discharge capacity of Li/Fe-doped NiS2 cells.