Building an Elastic Mechanical Network for Highly Efficient Silicon‐Based Anodes

Abstract

AbstractSilicon (Si), known for its high theoretical capacity, holds promise for developing high‐energy‐density lithium‐ion batteries (LIBs). However, the intrinsic low conductivity and substantial volume expansion limit its commercial application. Developing a binder that can suppress the massive volume expansion while improving Si conductivity is particularly important for LIBs based on Si anode. Here, grafting natural adhesive cationic guar gum (CGG) with small molecular acrylamide (AM) is proposed and applied it to the Si‐based anode. The rigid guar gum main chain and the elastic polymerized acrylamide (pAM) side chain forms a 3D network that completely encapsulated Si nanoparticles and cross‐linked with the natural hydroxyl groups on the surface of Si particles through abundant functional groups. Numerous link anchors and robust mechanical networks facilitate lithium‐ion transport and effectively mitigated the significant stress generated by silicon during charge and discharge cycles. Based on this innovative design, the Si@CGG@pAM@SP (Super P) electrode demonstrates excellent long‐term cycle stability and rate performance. The Si@CGG@pAM@SP electrode preserves 2086 mAh g−1 discharge capacity after 100 cycles (corresponding to 91.5% capacity retention). Physical characterization and electrochemical tests confirm the rationality of the polymer binder design, serving as a valuable reference for the material design of lithium‐ion batteries.