Robust polymeric coating enables the stable operation of silicon micro-plate anodes recovered from photovoltaic industry waste for high-performance Li-ion batteries

Abstract

Silicon is regarded as one of the most promising anode materials for next generation Li-ion batteries (LIBs). However, for the actual applications, a Si electrode must possess superior electrochemical properties, and the fabrication must be cost-effective and industrially scalable. Here, we report a highly scalable and low-cost route of recovering high-purity Si micro-plates from photovoltaic industry waste obtained during diamond-wire slicing of solar grade Si ingots, and demonstrate their great potential as high-performance anode materials with ideal cost. To accommodate the severe volume effect of Si micro-plates, a firmly anchored alginate coating layer is formed on the Si surface on the basis of the strong interactions between the oxidized Si and alginate carboxylic groups, which helps to construct a robust conductive network around Si micro-plates and allows the electrode architecture to be perfectly maintained even though the Si micro-plates are pulverized into nanoparticles. The recycled Si anode delivers high reversible capacity, superior rate capability and extraordinary cyclability. This new technology not only provides an abundant and low-cost Si source for LIB applications, but also effectively resolves the waste disposal issue of the photovoltaic industry, which may therefore bring about enormous environmental and economic benefits.