Adjusting Interfacial Reactions for Achieving Highly Stable Operation in Lithium Metal Batteries

Lithium-metal batteries (LMBs) are considered a promising candidate for next-generation high energy-density batteries. However, the unstable interface and dendrite growth severely restrict the commercial applications of lithium metal anodes. Here, we pioneeringly propose an electrolyte that consists of a simple cyclic vinylethylene carbonate (VEC) solvent and LiTFSI salt, enabling LMBs with high performance in the aspects of long cycle life and high Coulombic efficiency (CE). Jointed experimental and DFT calculations demonstrate that the favorable reduction of the VEC induces a uniform distribution of elastic organic polymer molecules at the anode surface with high mechanical strength, which reinforces the inorganic Li2CO3 and LiF underneath and maintains the integrality of the solid electrolyte interphase (SEI) film. The inorganic compounds display a high Li ion diffusion coefficient, surface energy, and Young’s modulus (10.71 GPa), which effectively accelerate the interfacial kinetics and homogenize the metallic Li deposition. In addition, the low solvation energy of the Li ions in the VEC effectively improves the desolvation process compared to traditional electrolytes. Thus, this organic/inorganic laminated SEI film enables an excellent CE of 98% after 450 cycles and highly stable cycling over 3000 h. This work provides a cost-effective proposal, paving the way for industrial applications of cyclic carbonate-based electrolytes in LMBs.