A multifunctional electrolyte with highly-coordinated solvation structure-in-nonsolvent for rechargeable lithium batteries

Rechargeable lithium-based battery is hailed as next-generation high-energy-density battery systems. However, growth of lithium dendrites, shuttle effect of lithium polysulfides intermediates and unstable interphase of high-voltage intercalation-type cathodes largely prevent their practical deployment. Herein, to fully conquer the three challenges via one strategy, a novel electrolyte with highly-coordinated solvation structure-in-nonsolvent is designed. On account of the particular electrolyte structure, the shuttle effect is completely suppressed by quasi-solid conversion of S species in Li-S batteries, with a stable cycle performance even at lean electrolyte (5 μL mg⁻¹). Simultaneously, in-situ-formed highly-fluorinated interphases can not only lower Li⁺ diffusion barrier to ensure uniform nucleation of Li but also improve stability of NCM cathodes, which enable excellent capacity retention of Li‖LiNi_0.5Co_0.2Mn_0.3O₂ batteries under conditions toward practical applications (high loading of 2.7 mAh cm⁻² and lean electrolyte of 5 mL Ah⁻¹). Besides, the electrolyte is also nonflammable. This electrolyte structure offers useful guidelines for the design of novel organic electrolytes for practical lithium-based batteries.