Petroleum waste hydrocarbon resin as a carbon source modified on a Si composite as a superior anode material in lithium ion batteries

We demonstrate impressive electrochemical performance of a silicon(Si)/carbon(C) composite prepared by mixing an appropriate concentration of hydrocarbon resin, Si powder, and polyacrylic acid followed by a simple ball milling process and heat treatment at temperatures ranging from 600°C to 900 °C. The Si/C composite annealed at 700 °C achieved a significantly high discharge capacity (2291 mAh g⁻¹) in the first cycle, very good cyclic stability (1402 mAh g⁻¹ after 100 cycles), and excellent rate capability (1020 mAh g⁻¹ at 2C with a retention of 95.5%). The composites annealed at high temperatures (800 °C and 900 °C) also displayed good capacity (1330 mAh g⁻¹, 1340 mAh g⁻¹) after 100 cycles and high rate capability (676 mAh g⁻¹, 619 mAh g⁻¹ @2C). indicating outstanding physical/chemical/structural stability of the composite that makes it a very suitable anode material in lithium ion batteries. The annealing temperature led to the formation of a C, SiOC/SiOx layer over the Si, as observed through a microstructure analysis, and different degrees of oxidation of the Si were observed using X-ray photoelectron spectroscopy. A detailed, comprehensive analysis of the structure/microstructure, bond vibrations, oxidation states of Si, and electrochemical performance is carried out.