Covariance of interphasic properties and fast chargeability of energy-dense lithium metal batteries

Lithium metal batteries can achieve high energy density, alleviating range anxiety for electric vehicles. However, the rational interphase design under fast charging conditions remains difficult. Here we explore a series of pyran-based electrolytes with various substitutional anions under a fast charging condition and observe weakly Li+-associating anions facilitating uniform lithium plating under a fast charging condition. We demonstrate lithium metal batteries achieving a 5–70% state of charge (SoC) within 12 min over 350 repeated cycles at a 4C (8.4 mA cm−2) charging rate, as well as high-energy designs delivering projected energy densities of 386 Wh kg−1 reaching a 10–80% SoC within 17 min over 180 cycles. We propose that the improved fast charging performance is in tandem with the ability of the weakly Li+ associating anions to suppress inorganic species clustering within the solid–electrolyte interphase and demonstrate the potential for electrolyte advancement based on the proposed mechanism. Lithium metal batteries offer high energy density for electric vehicles but face challenges with fast charging. This study investigates pyran-based electrolytes containing various substituted anions, revealing that weakly Li+-associating anions enhance fast-charging performance.