• The succinonitrile-based deep eutectic electrolyte, characterized by strong ion–dipole interactions, can establish an anion-rich Li+ solvation structure while exhibiting high ionic conductivity and Li+ transference number.
• Precisely regulating multiple ion–ion, ion–dipole, and dipole–dipole interactions facilitates the transition of the Li+ solvation structure from solvent dominance to anion dominance.
• Optical microscopy and Micro-CT analysis can demonstrate that the anion-derived solid electrolyte interphase effectively mitigates the irreversible volume expansion of silicon oxide.
• The SiO|LiCoO2 full cells exhibit excellent electrochemical performance in deep eutectic-based electrolytes, presenting an effective strategy for extending the cycle life of SiO anodes.