Investigation of effective bonding between varied binders and Si anode with different particle sizes

Abstract

The size of silicon (Si) particles and used binder directly affects the flow uniformity of the slurry, the mechanical properties, and the electrochemical performance of the electrode. In this study, we tried to clarify the adaptation law of Guar gum (GG) and sodium alginate (SA) with 200 nm-Si and 1 μm-Si from the above-mentioned aspects. The rheological properties of the slurry showed that the slurry with GG due to the gelatinization had a poorer dispersion than that with SA. The tests of zeta potentials, thermogravimetric analysis, peeling-off, and nano-indentation profiles explained the performance differences of the electrodes from the mechanical properties. Because of more hydrogen bond sites, the discharge specific capacity of the nm-Si/GG electrode (1116.05 mA h g−1) was higher than the nm-Si/SA electrode (657.74 mA h g−1) after 70 cycles. On the contrary, the μm-Si/SA electrode owing to a rigid skeleton in the SA molecule exhibited a discharge specific capacity of 1681.47 mA h g−1 after 50 cycles, while the μm-Si/GG electrode was 486.58 mA h g−1. In addition, the results inspire more reasonable optimization of the Si-based electrode design.