Fluorobenzene-based diluted highly concentrated carbonate electrolyte for practical high-voltage lithium metal batteries

Lithium metal battery (LMB) is regarded as a rising star for next generation high energy density batteries. However, there is still a great challenge to achieve stable cycling of high-voltage LMBs, especially under practical conditions. Herein, we report a fluorobenzene-based (FB-based) diluted highly concentrated carbonate electrolyte with significantly improved physical and electrochemical properties. Employing FB as the diluent not only reduces the viscosity, density and cost of highly concentrated electrolyte, but also contributes to the formation of layer-like solid electrolyte interphase with enriched LiF. The collective superiority enables outstanding cycling stability of lithium metal anode. Consequently, Li||LiNi 0·6 Co 0·2 Mn 0·2 O 2 batteries with high areal capacity (3.6 mAh cm −2 ) based on such electrolyte show excellent cycling performance under a range of realistic conditions, including lean electrolyte (3 g Ah −1 ), low-temperature (−20 °C), and limited Li source (50 μm). This work provides a facile but effective method to achieve a stable high-voltage LMBs and demonstrates its potential in practical application. • Fluorobenzene dilutes highly concentrated carbonate electrolytes. • Fluorobenzene endows electrolyte unique interfacial chemistry. • Modified electrolyte applies for high-voltage lithium metal batteries. • Full cell obtains excellent cycling performance under practical conditions.