Constructing Silicon Nanosheet/Graphite Nanosheet Composite from Retired Photovoltaic Silicon as Lithium-Ion Battery Anode

Abstract

The huge materials and energy consumption flows in modern society bring enormous pressure to environment and resource. Compared with production of silicon powder from natural resources via the long chain of chemical engineering approaches with high energy consumption and giant pollutants emission, direct use of large amount of silicon waste from retired photovoltaic devices is low cost, resources/energy saving property, and environmental protection value. Herein, silicon waste is sand ground into nanosheets and composited with graphite nanosheets followed by carbon wrapping to obtain final composite anode materials. The silicon nanosheet/graphite nanosheet stacked structure within the composite, which delivers electrons perpendicular to planar interfaces in short distance and depresses internal stress accumulation via the separation of silicon nanosheet by graphite nanosheet, along with further separation of silicon nanophase by amorphous phase SiO_x within silicon nanosheet, provides good stability of bulk anode during the cyclic charge/discharge process.