Unlocking the longevity of graphite-based batteries in ether electrolytes through solvent-Co-intercalation-resistant electrolyte design

Ether-based electrolytes are attractive for silicon-carbon composite (Si/C) anodes; however, their long-term application is hindered by the strong tendency of solvent co-intercalation into graphite. Consequently, achieving durable graphite operation requires an electrolyte that not only enables initial solvent-free lithiation but also maintains a high barrier against solvent co-intercalation throughout prolonged cycling. Herein, we develop an ethylene glycol dibutyl ether-based electrolyte to address this challenge. The elevated co-intercalation resistance arises from three key features: weak Li + solvation with a facilitated desolvation process, suppression of early-stage graphite damage that could otherwise create solvent-insertion pathways, and the formation of a dense organic-inorganic hybrid solid electrolyte interphase (SEI) that blocks solvent permeation during cycling. Collectively, these features sustain pure Li + intercalation in graphite for over 2.4 years of continuous operation in Li||graphite battery and enable a 5 Ah NCM811||Si/C pouch cell to achieve a gravimetric energy density of 287 Wh kg −1 .