A self-adsorption molecule passivated interface enables efficient and stable lithium metal batteries

Abstract

Despite the theoretical promise of attaining high energy densities, practical applications of lithium metal batteries (LMBs) remain hindered by the inadequacies of the electrode/electrolyte interface and unsatisfied cycling stability. Herein, a self-adsorption molecule with polar groups was designed and introduced in ether electrolyte, aiming to form a high-density and ordered molecular layer occupying active sites on the electrode surface, while restricting electrolyte molecule penetration into the interface. This self-adsorption molecule favors the formation of a robust anion-rich cathode/anode electrolyte interphase due to the change of the interfacial solvation structure, thus inhibiting solvent decomposition and enhancing interfacial stability. Consequently, the addition of this molecule into low-concentration ether electrolytes notably upgrades the electrochemical performance of the LiNi_0.8Co_0.1Mn_0.1O₂ (NCM811)||Li battery, which enables a high capacity retention of 87.2% after 250 cycles at 4.5 V. Moreover, the NMC811||Li pouch cells achieve stable cycling over 150 cycles with a capacity retention of 92.9% at a low negative/positive capacity ratio of 2.7 with a lean electrolyte. This interface passivation design strategy provides a promising path toward high-energy, durable, and safe rechargeable LMBs.