All-solid-state batteries resolve the safety issues of flammable liquid electrolytes while providing high energy density. Sulfide-based solid electrolytes, offering liquid-like ionic conductivity even at room temperature, are among the most actively applied. Solution-based electrode fabrication is compatible with existing lithium-ion processes, where the solvent disperses the electrolyte and the binder ensures interfacial adhesion. However, sulfide electrolytes are vulnerable to structural damage in polar solvents, leading to performance degradation.This can be mitigated using low-polarity solvent-binder systems, though poor binder adhesion remains a challenge. To address this, we aimed to optimize binder structure through '-ene' functionalization. Specifically, we performed thiol-ene reactions to partially graft polar thiol groups onto the double bonds of a PS-PI-PS (SIS) triblock copolymer, focusing on controlling the reaction conversion and improving selectivity.