TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Method: In the method (M1), the initiating the reaction of the SiI4 with Mg2Si step, or step of reacting the SiI4 with the Mg2Si involves adding a predetermined amount of ethanol. The initiating reaction of the SiI4 with CaSi step, or the step of reacting SiI4 with CaSi involves resistively heating the powder using a nichrome wire. The initiating the reaction of the SiI4 with the CaSi step, or the step of reacting SiI4 with CaSi involves ball milling the SiI4 and CaSi together. The method (M1) further involves washing a salt by-product from the nanostructured silicon with a solution selected from water and/or alcohol; removing a native oxygen layer from the nanostructured silicon by an etching treatment comprising hydrofluoric acid; and adding tin prior to the initiating step. In the method (M2), the combining step a3) involves grinding the stoichiometric mixture of silicon tetraiodide and germanium based precursor into a homogeneous powder; or ball milling the mixture of silicon tetraiodide and the germanium based precursor into a homogeneous powder, where the grinding the stoichiometric mixture of silicon tetraiodide and an germanium based precursor into a homogeneous powder is done in a glove box filled with argon and helium. The initiating reaction of the SiI4 with the germanium based precursor involves resistively heating the homogenous powder using nichrome wire; or adding a predetermined amount of ethanol. The method (M2) further involves: washing a salt by-product from the nanostructured silicon-germanium with a solution selected from water and/or alcohol; and removing a native oxygen layer from the nanostructured silicon by an etching treatment comprising hydrofluoric acid. Preferred Components: The alkaline earth metal silicide is selected from magnesium silicide (Mg2Si) or calcium silicide (CaSi). The germanium based precursor is selected from magnesium germanide (Mg2Ge) or germanium iodide (GeI4). EXAMPLE - No suitable example given.