Multi-Functional AgNO3 Preplanted in Li Metal Powder Electrodes

Abstract

Li metal powder (LMP) is very promising in practically fabricating thin Li electrodes for high-energy-density Li metal batteries (LMBs), because it allows not only conventional slurry coating but also co-use of functional additives. Also, the LMP has several times higher surface area than that of the Li foil with tens of micrometers, which reduces the local current density and suppresses Li dendritic growth. However, the uneven and resistive protection layer on the LMP surface could lead to the non-uniform composition in solid electrolyte interphase (SEI), thereby resulting in the localized Li nucleation and growth. Thus, the introduction of stabilizing additives for LMP is one of the most promising solutions to control the Li stripping/plating behavior. Herein, we report a AgNO3-preplanted LMP electrode having stable long-term cycle performance. The AgNO3 in the slurry mixing and coating process can chemically form lithiophilic Ag particles on the LMP surface, which act as nucleation sites. In addition, since the metallic Ag particle is embedded within the LMP electrodes, it continuously contributes as the seeding points even under extreme volume expansion during cycling. Additionally, nitrates can help form Li3N-rich SEI with higher ionic conductivity and Young’s modulus. Finally, AgNO3-preplanted LMP electrode of 40 μm survives up to 500 cycles with 86.8% capacity retention at 1C/3C charging/discharging condition. Therefore, this superior cycle performance enables AgNO3-preplanted LMP electrodes to be an attractive anode candidate for LMBs.