A compared investigation of different biogum polymer binders for silicon anode of lithium-ion batteries

Binders have been confirmed to play a significant role in improving the cycling performance of Si anode. Some of natural biogum binders are exploited and related progresses are also achieved. However, the distinction of characteristics among different biogum binders as well as corresponding mechanisms and principles still remain to be elucidated. In this study, gum arabic (GA), guar gum (GG), and xanthan gum (XG) are selected for comparison. The highest initial Coulombic efficiency (ICE) of 90.4% is obtained with GA owing to diverse multiple interactions with Si nanoparticles to form a homogeneous covering that could protect Si core against being exposed to electrolyte and generating SEI film, as well as strong covalent network to suppress the isolation of Si, while plastic damage occurs during repeated volume change of Si because of irreversible bonding nature. By contrast, hydrogen bonding between polar –OH groups with self-healing nature provides Si anodes with GG and XG better cycling stability, while the optimized capacity of 1323 mAh g−1 after 100 cycles is retained with GG due to the extra ability to transfer Li+. This study provides the design and selection principles for binders applied in Si anodes of lithium-ion batteries.