Silicon oxide (SiO_x) has outstanding capacity and stable lithium-ion uptake/removal electrochemistry as a lithium-ion anode material; however, its practical massive commercialization is encumbered by unavoidable challenges, such as dynamic volume changes during cycling and inherently inferior ionic conductivities. Recent literature has offered a consensus that binders play a critical role in affecting the electrochemical performance of Si-based electrodes. Herein, we report an aqueous binder, γ-polyglutamic acid cross-linked by epichlorohydrin (PGA-ECH), that guarantees enhanced properties for SiOanodes to implement long-term cycling stability. The abundant amide, carboxyl, and hydroxyl groups in the binder structure form strong interactions with the SiOsurface, which contribute strong interfacial adhesion. The robust covalent interactions and strong supramolecular interactions in the binder ensure mechanical strength and elasticity. Additionally, the interactions between lithium ions and oxygen (nitrogen) atoms of carboxylate (peptide) bonds, which serve as a Lewis base, facilitate the diffusion of lithium ions. A SiOanode using this PGA-ECH binder exhibits an impressive initial discharge capacity of 1962 mA h gand maintains a high capacity of 900 mA h gafter 500 cycles at 500 mA g. Meanwhile, the assembled SiO||LiNiCoMnOfull cell shows a reversible capacity of 155 mA gand displays 73% capacity retention after 100 cycles.