 Porous silicon nanoparticles are more reactive than bulk silicon materials and tend to have a higher weight percentage of silica as a result of the smaller size.Porous materials allow for internal volume expansion to help control overall materials expansion.Methods include a silicon anode with an energy density above 1,100 mAh/g and a durability of 600 cycles that used porous silicon particles using ball-milling and stain-etching.