Effect of silicone segment and imidization of polyimide-based binder on the electrochemical performances of high silicon content anode for lithium-ion batteries

Binders are expected to play important role in silicon-based anode materials, but have not been well explored. In this work, a serial of silicon containing polyimides and polyamides have been synthesized and used as the binder of high content (80wt%) silicon anode. Systematic characterizations have been done on the chemical structures, physical properties of the binders, and the electrochemical performances of silicon-based anode. It was found that the swelling ratio, adhesion strength, and hardness plays important roles on the initial Coulombic efficiency (ICE) and capacity retention of silicon-based anode, and these parameters highly depend on the types and properties of binders. After optimizing the chemical structures and physical properties of the binders, a high specific capacity of 2941 mAh g-1, relatively high initial Coulombic efficiency (ICE) of 83%, and good capacity retention of 85% (after 200 cycles) have been obtained. These results would help researchers to design new types of binders for silicon-based anode to improve its ICE and capacity stability.

Automated summary

In this study, a series of silicon containing polyimides and polyamides were synthesized and characterized as binders for silicon-based anodes. It was found that the swelling ratio, adhesion strength, and hardness of the binders played important roles in the initial Coulombic efficiency (ICE) and capacity retention of silicon-based anodes. By optimizing the chemical structures and physical properties of the binders, high specific capacity, high initial Coulombic efficiency, and good capacity retention were achieved.