Carbonate-Based Localized High Concentrated Electrolyte for Long-Cycle-Life Lithium Metal Batteries

Abstract

Rechargeable Lithium Metal Batteries (LMBs) using high-voltage cathodes can deliver the highest possible energy densities among all electro-chemistries. However, the notorious reactivity of metallic lithium as well as the catalytic nature of the cathode materials largely prevent their practical application. Here, we demonstrate a formulated carbonate-based high concentrated electrolyte with LiPF6 that supports the most commercial aggressive and high-voltage cathode to realize a highly stable Li metal full-cell with limited metallic Li. The formation of stable Li2O/LiF-rich solid electrolyte interface (SEI) layers afforded stable operations of resultant LMBs under practical working conditions. Our electrolyte contributes to both high efficiency of 99.5% for Li||Cu half cell and ~100% for lithium full cells based on 4.3 V Ni-rich LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes. Notably, at a loading of 4.0 mAh.cm−2, our full cells showed a capacity retention of ~80% over 280 cycles at lean electrolyte condition of 5 μL.mAh-1. The effective stabilization that inhibited the aggressive chemistries at extreme potentials in LMBs upon practical conditions by our electrolyte was determined to be the formation of the dense, inorganic-rich interphase.