An Interlayer Containing Dissociated LiNO₃ with Fast Release Speed for Stable Lithium Metal Batteries with 400 Wh kg⁻¹ Energy Density

Abstract Lithium metal is an ideal electrode material for future rechargeable batteries. However, dendrite formation and unstable solid electrolyte interphase film lead to safety concerns and poor Coulombic efficiency (CE). LiNO₃ significantly improves the performance of the lithium metal anode in ester electrolytes but its use is restricted by low solubility. To increase the content of LiNO₃ in the cell, a poly‐(vinyl carbonate) organogel interlayer containing dissociated LiNO₃ (LNO‐PVC) is placed between the cathode and anode. The dissociated LiNO₃ effectively increases the LiNO₃‐release rate and compensates for the LiNO₃ consumed in ester electrolytes during cycling. Via this interlayer, the performance of the lithium metal anode is significantly improved. The average CE of a Li‐Cu cell reaches 98.6% at 0.5 mA cm⁻²‐1 h and 98.5% at 1 mA cm⁻²‐1 h for 300 cycles. Also, a Li||NCM811 pouch cell with LNO‐PVC interlayer can also reach a 400 Wh kg⁻¹ energy density with a cycling life of 65 cycles. This strategy sheds light on the effect of the state of this salt on its release/dissolution kinetics, which is determined by the interactions between the salt and host material.