A Novel Degradable Three-Dimensional Binder DSM-g-PAA-c-PEG for a High-Performance Si Anode in Lithium-Ion Batteries

Silicon anodes have been extensively researched due to their high capacity and potential to revolutionize energy storage. However, during lithiation and delithiation cycles, the volume expansion of silicon anodes can lead to mechanical damage and significant capacity decay. To address this issue, three-dimensional polymer binders have been introduced to suppress volume changes by providing mechanical support. Although cross-linking in these binders improves their robustness, current options with high molecular weights and cross-linked structures are not biodegradable. To provide an environmentally friendly solution, we propose grafting degradable starch microspheres (DSM) with poly(acrylic acid) (PAA) and cross-linking with polyethylene glycol (PEG) to form DSM-g-PAA-c-PEG, a binder that demonstrates strong adhesive properties and superior mechanical strength compared to PAA. The UV-Visible spectrum confirms DSM’s continued degradability. After cycling the Si@DSM-g-PAA-c-PEG anode 100 times at 0.25 C, it achieves a capacity retention rate of 58.1 % with a reversible capacity of 2127.8 mAh g −1 . This work provides new insight into the engineering of next-generation silicon electrode using an environmentally-friendly binding strategy, which may advance the large-scale industrial application of lithium-ion batteries.