Modulation of desolvation barriers and inhibition of lithium dendrites based on lithophilic electrolyte additives for lithium metal anode

Abstract

Lithium metal has emerged as a highly promising anode material for enhancing the energy density of secondary batteries, attributed to its high theoretical specific capacity and low electrochemical potential. However, safety concerns related to lithium dendrite-induced short circuits and suboptimal electrochemical performance have impeded the commercial viability of lithium metal batteries. Current research efforts primarily focus on altering the solvated structure of Li⁺ by modifying the current collector or introducing electrolyte additives to lower the nucleation barrier, expedite the desolvation process, and suppress the growth of lithium dendrites. Nevertheless, an integrated approach that combines the advantages of these two strategies remains elusive. In this study, we successfully employed metal-organic salt additives with lithophilic properties to accelerate the desolvation process, reduce the nucleation barrier of Li⁺, and modulate its solvated structure. This approach enhanced the inorganic compound content in the solid electrolyte interphase (SEI) on lithium foil surfaces, leading to stable Li⁺ deposition and stripping. Specifically, Li||Cu cells demonstrated excellent cycle life and Coulombic efficiency (97.28% and 98.59%, respectively) at 0.5 mA/cm²@0.5 mAh/cm² and 1 mA/cm²@1 mAh/cm² for 410 and 240 cycles, respectively. Li||Li symmetrical cells showed no short circuit at 1 mA/cm²@1 mAh/cm² for 1150 h, and Li||LFP full cells retained 68.9% of their capacity (104.6 mAh/g) after 250 cycles at N/P (1.1:1.0) with a current density of 1 C.