Abstract
Ball milling impact into polymeric binder for Li-ion silicon-based negative electrode slurry was for the first time investigated. The poly(acrylic acid) degradation characterization is carried out and a solution is proposed in the form of new milling-free formulation development. [(Si+C)SPEX+B]MAG formulation then allows a capacity retention increase from 65 to 84 % at the 20th cycle for silicon rich electrode thanks to the polymeric binder ball milling deleterious absence. A polymer, poly(fumaric acid), is synthetized and used for the first time as silicon-based negative electrode binder. Its modest performance is improved by increasing its average molecular mass and the formulation developed during this work. Altough the electrochemical results of the electrodes based on this polymer are lower than those using PAA but optimizations are possible to improve its performance as a binder. Finally, the transposition of these works was carried out on two other negative electrode materials for Li-ion batteries: TiSnSb and silicon-graphite composite. As described in the literature, the silicon-based electrodes improvements are not strictly transposable to TiSnSb and the electrodes based on this material do not benefit from a significant improvement in their lifetime thanks to the formulation developed. The study of various weight ratios of Si:Gr shows that the silicon content should not be higher than 30 % in mass in the active material to allow interesting capacity retentions