Topological Structure Design of Ether Solvents for Lithium Storage Chemistry in Graphite Anode

Ether-based electrolytes hold great promise for next-generation lithium-ion batteries (LIBs) owing to their low melting points and viscosities. However, their strong solvation ability promotes detrimental Li⁺-solvent co-intercalation, leading to graphite exfoliation and limiting practical applications. Here, we employ topological structure engineering of ether solvents and demonstrate a synergistic mechanism of electronic effects (electropositivity defined by ESP_max/electronegativity defined by ESP_min) and volume of solvent in modulating lithium storage behavior in graphite. We demonstrate that increased stability (as indicated by enhanced |ESP_min| - ESP_max) and reduced volume of Li⁺-solvent complexes enhance the tendency for co-intercalation. This necessitates the use of solvents featuring enriched base structures (─C₂H₄O─) and shorter terminal alkyl chain lengths (─C₂H₄). Furthermore, we reveal that the primary cause of capacity decay during Li⁺-ether co-intercalation processes is the continuous rupture and reformation of the solid electrolyte interphase (SEI). This work provides new insights into designing ether-based electrolytes that compatible with graphite, paving a new way to develop high-performance LIBs.