《“In−N−Out” Design Enabling High−Content Triethyl Phos-phate−Based Non−Flammable and High−Conductivity Electro-lyte for Lithium−Ion Batteries》

Safety issues related to flammable electrolytes in lithium−ion batteries (LIBs) remain a major challenge for their extended application. The use of non−flammable phosphate−based electrolytes has been proved the validity in inhibiting the com-bustion of LIBs. However, the strong interaction between Li+ and phosphate leads to a dominant solid electrolyte interphase (SEI) with limited electronic shielding, resulting in poor Li+ intercalation at the graphite (Gr) anode when using high−phosphate−content electrolytes. To mitigate this issue and improve Li+ insertion, we propose an “In−N−Out” strategy to render phosphate “non−coordinative”. By employing a combination of strongly polar solvents for a “block effect” and weakly polar solvents for a “drag effect”, we reduce the Li+−phosphate interaction. As a result, phosphate remains in the electrolyte phase (“In”), minimizing its impact on the incompatibility with the Gr electrode (“Out”). We have developed a non−flammable electrolyte with high triethyl phosphate (TEP) content (>60 wt.%), demonstrating excellent ion conductivity (5.94 mS/cm at 30 ⁰C) and reversible Li+ intercalation at a standard concentration (~1 M). This approach enables the manipulation of multiple electrolyte functions and holds promise for the development of safe electrochemical energy storage systems using non−flammable electrolytes.

https://www.x-mol.com/paper/1706012659835228160?adv