Non-polar ether-based electrolyte solutions for stable high-voltage non- aqueous lithium metal batteries

Z Li and H Rao and R Atwi and BM Sivakumar and B Gwalani and S Gray and KS Han and TA Everett and TA Ajantiwalay and V Murugesan and NN Rajput and VG Pol, NATURE COMMUNICATIONS, 14, 868 (2023).

DOI: 10.1038/s41467-023-36647-1

The electrochemical instability of ether-based electrolyte solutions hinders their practical applications in high-voltage Li metal batteries. To circumvent this issue, here, we propose a dilution strategy to lose the Li+/solvent interaction and use the dilute non-aqueous electrolyte solution in high-voltage lithium metal batteries. We demonstrate that in a non-polar dipropyl ether (DPE)-based electrolyte solution with lithium bis(fluorosulfonyl) imide salt, the decomposition order of solvated species can be adjusted to promote the Li+/salt-derived anion clusters decomposition over free ether solvent molecules. This selective mechanism favors the formation of a robust cathode electrolyte interphase (CEI) and a solvent-deficient electric double-layer structure at the positive electrode interface. When the DPE-based electrolyte is tested in combination with a Li metal negative electrode (50 mu m thick) and a LiNi0.8Co0.1Mn0.1O2-based positive electrode (3.3 mAh/cm(2)) in pouch cell configuration at 25 degrees C, a specific discharge capacity retention of about 74% after 150 cycles (0.33 and 1mA/cm(2) charge and discharge, respectively) is obtained. Ether solvents have poor anodic stabilities in lithium metal batteries. Here, the authors propose a non- aqueous electrolyte solution with a non-polar and non-fluorinated ether solvent. The electrolyte enables stable cycling of high-voltage Li metal batteries in pouch cell configuration.

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