All-Silicon Energy Storage (ASES)

Abstract

Silicon is an ideal candidate to build massive energy storage solutions owing to its low cost (~$1.7/kg) and abundance on earth. In this work, we describe a novel concept for energy storage in which the energy is stored in the form of silicon's latent heat and converted to electricity upon demand by thermophotovoltaic (TPV) cells. This approach takes advantage of the extremely high latent heat (1.8 MJ/kg) and melting point (1410ºC) of silicon, and the low weight and silent operation of the TPV cells. The proposed solution has potential to provide total energy (heat plus electricity) storage densities approaching 1 MWh/m3, which is 12-15 times higher than that of lead-acid batteries, 2-5 times than that of Li-ion batteries and 10-20 times than that of the molten salt PCMs utilized in CSP systems. In the proposed system, 10-50% of the total energy could be delivered in the form of electricity, depending on the particular TPV cell characteristics, and the remaining energy is supplied as heat (e.g. hot water) which could be used in homes or factories.