[Favors] ground salt and magnesium into the purified quartz and heated the resulting powder. In this very simple process, the salt acted as a heat absorber while the magnesium removed oxygen from the quartz, resulting in pure silicon. More than that, the pure nano-silicon formed in a very porous, 3D silicon sponge-like consistency. Porosity is one of the keys to improving the performance of battery anodes as it provides a large surface area and allows lithium ions to travel through them more quickly.