Low-Temperature Chemical Passivation Routes for Integration of Supercapacitors Directly into Silicon Solar Cells

Due to the intermittent nature of renewable energy sources such as solar and wind energy, systems designed to convert grid-scale power from these resources must be coupled with energy storage for off-grid operation.  Traditional routes to coupling energy storage with energy conversion systems consists of an energy storage device situated external to the energy conversion system.  However, direct integration of both systems offers numerous advantages, such as multipurposing of materials and storage directly at the point of generation to mitigate DC-AC inversion.  Our recent efforts have demonstrated the ability to utilize the excess silicon material in a polycrystalline solar cell for supercapacitor energy storage applications.  However, a key challenge that remains is to develop chemical passivation routes at low temperatures that can preserve the solar cell P-N junction and yield a passive silicon energy storage interface with a solid-state electrolyte.  We address this issue by exploring multiple routes for low-temperature passivation, specifically including (i) wet chemical passivation of porous silicon using thin film metal coatings, and (ii) electrochemical passivation of porous silicon using conductive polymer networks.  Our efforts demonstrate these passivation routes as being promising for the development of fully integrated energy storage and conversion systems applicable toward a range of applications ranging from grid-scale storage to remote energy transfer applications.