Graft copolymer, method for preparing the same, polymer binder for silicon anodes comprising the same, silicon anode comprising said polymer binder, and lithium-ion battery comprising said silicon anode

Silicon Anode Binder Combining UPy Self-Healing Side Chains and PEG Ion-Conductive Side Chains

This technology is a 3D network-based polymer binder that incorporates self-healing ureido-pyrimidinone (UPy) side chains and ion-conductive poly(ethylene glycol) (PEG) side chains into a polyacrylic acid backbone, buffering silicon volume expansion while securing lithium-ion transport pathways.

Silicon anodes suffer from significant volume expansion and contraction during charge and discharge cycles, leading to particle pulverization and SEI layer degradation. These issues cause the active material to detach from the current collector and the electrode structure to collapse, limiting battery lifespan and efficiency.

This technology utilizes a graft copolymer binder that provides self-healing functionality through reversible UPy hydrogen bonding and enhances ion conductivity via PEG grafting, allowing the physical network within the electrode to recover from structural damage. Applicable to high-capacity next-generation silicon-rich anodes and long-life EV anode slurries, it maintains over 96% coulombic efficiency for 350 cycles while simultaneously reducing ion transport resistance.

‍

‍

Key Features:

• A graft copolymer backbone comprising polyacrylic acid with functional side chains bonded to both ends
• Side chains bonded to both ends of the backbone, comprising ureido-pyrimidinone functionalized with acrylate groups and poly(ethylene glycol) functionalized with methyl methacrylate groups
• A step of adding functionalized UPy, an acrylate-based compound, and functionalized PEG to an organic solvent and polymerizing them in the presence of an initiator
• A step of adding an acid catalyst to the polymerization product and performing a hydrolysis reaction to obtain the graft copolymer

‍