《Ethylene carbonate regulated solvation of triethyl phosphate to enable high‒conductivity, nonflammable, and graphite compatible electrolyte》

In the landscape of lithium‒ion batteries (LIBs), carbonate‒based electrolytes have driven remarkable progress, but persistent safety concerns stemming from their flammability necessitate innovative solutions. This study explores a cost‒effective nonflammable cosolvent, triethyl phosphate (TEP), to counter the risk. However, TEP's strong Li+‒coordinating propensity adversely affects graphite (Gr) electrode intercalation. To surmount these challenges, we unveil the competitive coordination behavior of TEP and ethylene carbonate, strategically optimizing TEP’s coordination numbers. This tailored approach culminates in a dynamically stable structure with reduced TEP’s adverse effects. Leveraging these insights, we engineer a TEP‒modified carbonate electrolyte with standard Li salts' concentration (1 M) boasting both non‒flammability and high ionic conductivity, ensuring Gr anode to achieve ~100% capacity retention after 150 cycles. Additionally, this formulation significantly minimizes fire and explosion risks in 4 A h Gr||LiNi_0.9Co_0.05Mn_0.05O₂ pouch cell during mechanical stress, exemplifying profound implications for safer energy storage of LIBs.

https://pubs.acs.org/doi/full/10.1021/acsenergylett.3c02414