Regulating ion transport in lithium metal batteries via metal-organic frameworks electrolyte modulator

Abstract

Low Li⁺ transference number in liquid electrolytes can lead to uneven lithium deposition and dendrite growth, reducing coulombic efficiency and cycle life of lithium metal batteries. In this study, metal-organic frameworks (MOFs) are used as electrolyte modulator to regulate Li⁺ transport. The -NH₂ group introduced into MOFs can form hydrogen bonds with anions in the electrolyte, immobilizing these anions and thereby facilitating the migration of cations. As a result, a uniform and dense deposition morphology of lithium was achieved. The Li⁺ transference number is increased from 0.26 to 0.57. The assembled Li||Li symmetrical cell can stably cycle for over for 900 h with an average overpotential below 20 mV. In addition, the rate performance of the battery can be enhanced.