Lithium metal batteries (LMBs) employing high-voltage cathode present a promising pathway toward high-energy-density energy storage systems. However, critical challenges have hindered their practical application, including lithium dendrite proliferation, unstable solid-electrolyte interphase (SEI), and limited oxidative stability of conventional 1,2-dimethoxyethane (DME)-based electrolytes. Herein, we rationally design a siloxane-based electrolyte system featuring enhanced oxidative stability through solvent molecular engineering. The Si-O bonding in siloxanes demonstrates superior bond energy compared to conventional C-O bonds in DME, which enables remarkable oxidative stability and the compatibility of high-voltage LMBs. Through in-operando Raman spectroscopy and molecular dynamics simulations, we reveal that more FSI