Bio-Based Adenine-Derived Polyimide as a Dual-Functional Binder for the Silicon Anode in Lithium-Ion Batteries

Silicon represents one of the most promising candidates for anode materials in the forthcoming generation of lithium-ion batteries. However, the practical implementation of silicon as an anode material is hindered by the tremendous volume expansion during battery cycling, ultimately leading to a rapid capacity degradation. The development of advanced binders stands out as a highly effective strategy for enhancing the cycling stability of silicon anodes. Herein, we construct bio-based adenine-containing polyimides (APIs) as a dual-functional binder for lithium-ion batteries. Due to the dual interfacial interactions of adenine segments with the silicon and the conductive carbon, the API can restrain the silicon volume expansion and maintain the electrode structure integrity, contributing to the stable solid electrolyte interphase and improved conductivity pathway. Compared with the conventional polyimides (PI), API exhibits slower capacity decay and excellent rate performance, as well as better cycling stability than poly(vinylidene fluoride), sodium carboxymethyl cellulose, and poly acrylic acid binders. This molecular structure design provides insights for the preparation of multifunctional high-performance binders for the silicon anode.