Provided herein are Si-based materials, methods of making the Si-based materials, and methods for using the Si-based materials. In embodiments, a silicon-based material comprises an aggregate of particles, the particles comprising an ordered array of nanostructures, the nanostructures comprising amorphous silicon, wherein at least some pairs of adjacent nanostructures are connected by one or more bridges comprising amorphous silicon, the one or more bridges extending from the surface of one nanostructure of the pair to the surface of the other nanostructure in the pair.