MECHANICAL GRINDING OF Si{sub}3N{sub}4 TO BE USED AS AN ELECTRODE IN LITHIUM BATTERIES

摘要

The effect of mechanical grinding on the electrochemical properties of Si{sub}3N{sub}4 is studied as the processing produces different particle size. The evolution of the amorphisation stage has been monitored by X-ray diffraction although particle size has also been studied through transmission electron microscopy experiments. Processed Si{sub}3N{sub}4 has been used as the positive electrode in electrochemical cells, where the negative electrode is lithium. We do not expect an intercalation process during the discharge step of such a type of cell, but a behaviour similar to that named as "convertible compounds". As the main result we can say that specific capacity of these lithium cells is increased up to a 34% in relation to the starting, non-milled material. However, even though we have reduced the size of the Si{sub}3N{sub}4 particles, from micrometers to nanometer scale, no appreciable changes in the cycling behavior is observed when compared with the pristine material.