A stable silicon anode based on the uniform dispersion of quantum dots in a polymer matrix

We propose a novel approach to the fabrication of silicon-containing anodes for lithium-ion batteries. Our approach is based on a liquid dispersion comprising of silicon quantum dots, carbon nanotubes and polyvinylpirrolidone (PVP) as a polymer additive. Coating of this dispersion onto copper foil followed by annealing in inert atmosphere allows the realization of a structure with good electrical conductivity, high specific surface area and with a carbon-based coating preventing the direct contact between the silicon particles and the electrolyte. This structure maintains a specific charge capacity of approximately 1000 mAh g−1 for 200 cycles and reaches a coulombic efficiency of 99.8%. The addition of PVP is a simple and scalable way of realizing, after annealing, a carbon-based matrix which surrounds the silicon particles and which greatly enhances the stability of the battery. The proposed process is based on commercially available carbon nanotubes, on silicon quantum dots which are produced using a scalable plasma-enhanced chemical vapour deposition technique, and is compatible with large area coating and processing techniques. The fabrication protocol described in this contribution represents a step towards the successful commercial utilization of silicon-based nanomaterials for energy storage applications.