Highly reversible and safe lithium metal batteries enabled by Non-flammable All-fluorinated carbonate electrolyte conjugated with 3D flexible MXene-based lithium anode

Abstract

Recognized as the most attractive and promising anode, Li metal has been pursued for its high specific capacity and lowest standard potential. However, the hazardous Li dendrite growth is one of the most challenging issues for LMB, which brings about fragile SEI formation, low CE, large volume change and even safety issues. To tackle these problems, we design a 3D flexible MXene based lithium metal anode to accommodate the volume changes, accelerate the charge transport and lower the specific current density. Moreover, nonflammable ternary all-fluorinated carbonate electrolyte system is proposed to construct stable interface by introducing LiF-rich SEI and address the safety concerns. With these synergetic effects, 3D Li-MXene anode in ternary all-fluorinated electrolyte shows significantly improved reversibility with high average CE at 94.5 % after 200 cycles. Full Li metal cell with LFP cathode, composited 3D anode and nonflammable electrolyte delivers high-capacity retention of 95.7 % at 300 mAh g−1 after 200 cycles and excellent rate ability. These results pave a new direction for developing high safety and high-performance Li metal batteries and can also be extended to other rechargeable metal-anode-based batteries such as Na/K/Mg/Ca et al.