Pulse Galvanostatic Synthesis of Zinc-Sulfur Nanocomposites and Application as a Novel Negative Material of Rechargeable Zinc-Manganese Dioxide Alkaline Batteries

Zinc-sulfur nanocomposite is prepared by using, zinc chloride (0.07 M), and sodium thiosulfate (0.09 M) as precursors in HCl solution with adjusted pH=1 by the pulsed current of 200 mA.cm-2 with a frequency of 18 Hz at 0 degrees C. The morphology, the particles sizes, and the composition of each synthesized sample are studied by SEM and XRD. The zinc-sulfur nanocomposite synthesized in optimum conditions includes halo-nanospheres with an average thickness of 50 nm. The sulfur content of the samples is increased when the synthesis temperature is increased. The sample synthesized at 0 degrees C with low sulfur content (similar to 25% wt) was used as negative (anode) material of rechargeable alkaline zinc-manganese dioxide (RAM) batteries. Some samples are synthesized in the absence of thiosulfate to form nanostructured zinc powder. The performance of zinc-sulfur nanocomposite as negative materials of RAM batteries is compared with those of commercial zinc powder and pure nanostructured zinc powder. The battery tests are shown a discharge capacity 300 mA.h.g(-1) for zinc-sulfur nanocomposite at first discharges (near to pure nanostructured zinc), but the cycle-life test showed that the zinc-sulfur nanocomposite has a longer cycle-life than the others do.