Enhanced cycle stability of silicon coated with waste poly(vinyl butyral)-directed carbon for lithium-ion battery anodes

Waste poly(vinyl butyral) (W-PVB) derived from the windshield glass of end-of-life vehicles is one of the most difficult waste resources to recycle. Therefore, almost all of the W-PVB is buried in landfill sites. Herein, carbon-coated Si (CCSi) as an anode for lithium ion batteries was synthesized using W-PVB as a carbon source via simple carbonization at a relatively low temperature. Commercial Si was well dispersed in ethyl alcohol solutions of W-PVB, leading to the formation of uniform carbon layers on the surface of the Si particles during carbonization. The amorphous carbon layers derived from W-PVB effectively mitigated the pulverization of the Si particles and side reactions between Si and the electrolytes, leading to a stable cycling performance with a retention as high as 77.5% without significant capacity fading. Furthermore, the anode exhibited high coulombic efficiency and an excellent rate capability of 910 mA h g−1 at a current density of 840 mA g−1. This facile and cost-effective synthesis of CCSi is expected to be applicable to other polymer-based industrial wastes as a new recycling strategy.