Interfacial modulation of bifunctional electrolyte additive engineering for dendrite-free and robust lithium metal anode

Abstract

Anode materials for rechargeable electric car batteries are obtained from Li-metal owing to their extremely high specific capacity and low redox potential. Unfortunately, safety concerns related to dendrite formation on the anode surface caused by the uneven distribution of Li-ions during the discharge process interfere with the use of Li-metal in industrial batteries. In this study, methyl vinyl sulfone (MVS), a sulfone-based functional electrolyte additive, is used in an additive engineering strategy to control Li-electrolyte interactions and address the aforementioned problems. Li dendrite growth may be restricted, and transition metal degradation on the surface of the cathode can be reduced by the MVS-derived functional electrolyte additive interfacial layer. The electrochemical performance of an ethylene carbonate/dimethyl carbonate (EC/DMC) + 1 wt% MVS Li-metal anode of a Li||Li symmetric cell exhibits remarkable cycle stability, maintaining a low overvoltage for over 750 h at 1 mA cm−2, and capacity of 1 mA h cm−2. Additionally, LiNi0.8Co0.1Mn0.1O2 (NCM811) full cells with the MVS additive exhibit enhanced electrochemical stability for 250 cycles at a current density of 100 mA g−1. This study provides an innovative approach for stabilizing the metal-electrolyte interfacial layer that may be used for practical applications in metal-based rechargeable batteries.