Promoting a Stable Interface Using Localized High-Concentration Carbonate-Based Electrolyte for Li Metal Batteries

Rechargeable lithium metal batteries (LMBs) using high-voltage cathodes have been attractive in delivering high-energy density, but it is still challenging to reach excellent cycling performance for practical applications due to the notorious reactivity of metallic lithium as well as the unstable nature of the cathode. Here, we demonstrate a formulated carbonated-based electrolyte with LiPF₆ that supports the most commercial aggressive and high-voltage cathode with the combination of cosolvent, diluent, and additives to address the issue in LMBs by providing a stable interface/interphase on both the anode and cathode. The electrolyte’s solvation structure is adjusted to reduce free carbonate solvents in the decomposition and contribution to the solid-electrolyte interphase (SEI) formation. The thin LiF-rich SEI and achieved uniform Li deposition afforded a high Coulombic efficiency of 99.5% for Li|Cu half cells and good cycling stability in Li||NMC811 full cells. The Li||NMC811 full cells showed good cycling life with a capacity retention of ∼80% over 280 cycles at an areal capacity of 4.0 mAh cm^-2, the lean electrolyte of 5 μL mAh^-1, and a thin 50 μm Li metal, demonstrating its advantage toward practical applications.