The effect of mechanical grinding (MG) on the electrochemical properties of Si3N4 is studied as the processing produces different particle size. The evolution of the amorphisation stage has been monitored by X-ray diffraction (XRD), although particle size has also been studied through transmission electron microscopy experiments. Processed Si3N4 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, the specific capacity of these lithium cells is increased up to 34% in relation to the starting, non-milled material. However, even though the size of the Si3N4 particles has been reduced, from micrometer to nanometer scale, no appreciable changes in the cycling behaviour is observed when compared with the pristine material. [Copyright &y& Elsevier]