A self-assembly capsule-like solvation structure electrolyte for lithium metal batteries

Abstract

The localized high-concentration electrolyte can be achieved by diluting a high-concentration electrolyte with an anti-solvent, which inherits the original solvation structural characteristics and reduces harmful interfacial reactions, resulting in an electrolyte with unique functions suitable for lithium metal batteries. Here, we design a localized high-concentration electrolyte with a capsule-like solvation structure and non-flammable properties to obtain stable-cycle and safe lithium metal batteries. The weak coordination and dipole-dipole interactions of fluorinated ether molecules promote the self-assembly of capsule-like solvated sheaths, encapsulating cations/anions and polar solvent molecules within the solvation sheath, which improves the oxidative stability of the electrolyte system and promotes the reduction of anions. A high-quality solid electrolyte layer was derived at the electrode interfaces, leading to rapid Li+ transport and dendrite-free lithium deposition. Consequently, a Coulombic efficiency of 99.7% is achieved, and the assembled Li||NCM811 battery exhibits a long cycle life of more than 400 cycles at 0.5C with a capacity retention of 83%. This work provides a promising approach for developing non-flammable electrolytes suitable for high-voltage lithium metal batteries.