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Tailoring Weakly Coordinating Electrolytes via Orbital-Overlap-Enhanced Dipole–dipole Interactions for Low-Temperature Lithium-Ion Batteries
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DOI：10.1002/adma.73982.png)
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Abstract
En 中文
Lithium-ion batteries (LIBs) suffer rapid capacity fade at low temperatures. Weakly coordinating electrolytes via adding low-polarity or non-coordinating co-solvents (such as fluorinated ethers) have shown promise in rapid desolvation, yet these electrolytes often exhibit low ionic conductivity at low temperature, limiting the application of high-energy density LIBs. Here, we design a weakly coordinating electrolyte by incorporating the non-coordinating co-solvent (pentafluoroethyl)trimethylsilane (PFTMS) into the coordinating solvent diethyl carbonate (DEC) via orbital-overlap-enhanced dipole–dipole interactions. The slight Si─O orbital overlap drives strong dipole–dipole interactions between PFTMS and DEC. This interaction lowers the negative electrostatic potential at the carbonyl oxygen of DEC, thereby weakening Li+-DEC coordination. Thus, by leveraging enhanced dipole–dipole interactions, this strategy realizes a weak Li+-solvent coordination through a lower content of PFTMS (10 vol%) compared to traditional fluorinated solvents. Besides, the designed electrolyte delivers sufficient ionic conductivity of 1.56 mS cm−1 at −40°C. Accordingly, the graphite || LiNi0.8Co0.1Mn0.1O2 (NCM811) coin cell shows reversible capacity of 156.5mAh g−1 at −40°C. Notably, 4.7 Ah graphite || NCM811 pouch cell also demonstrates 219.8 Wh kg−1 at −20°C. This work advances the design of traditional weakly coordinating electrolytes via an orbital overlap strategy, which paves the way for application in extreme environments.
Keywords:
dipole–dipole interactions
lithium ion batteries
low temperatures
orbital overlap
weakly coordinating electrolyte
Journal
IF:
26.8
Papers:
3.4W
Citations:
46.0W