Thermal treatment effect on electrochemical properties of silicon alloy anodes with poly(ether imide) binder for lithium-ion batteries

The development of silicon-based anodes with high capacity and good cycling stability for next-generation Li+ batteries (LIBs) is a very challenging task due to the large volume expansion of the electrodes during repeated cycling, which leads to fading in capacity. In this study, the electrochemical performance of Si alloy-based anodes with poly (ether imide) (PEI) binder is evaluated after thermal treatment at various temperatures. The systematic study revealed that the thermal treatment of the anodes with PEI binder at above 500 °C results in the partial carbonization of the PEI and remarkably enhances the electrochemical performance, such as cycle life and high rate capabilities. The partially carbonized PEI acts as both a binder and conductive additive for the Si-alloy anodes. This superior electrochemical performance is attributed to the strong adhesion of the partially carbonized PEI binder resulting from enhanced secondary interactions, which maintained good electrical contacts between the active materials, electronic conductors, and current collector during cycling. The partial carbonization strategy can be readily scaled up due to the facile heat treatment process, offering a new approach for developing next-generation high-capacity batteries.