Tidal Mixed Ionic/Electronic Conductive Interlayer Enables Supersmooth Lithium Deposition for Stable Lithium Metal Batteries

Lithium metal is the ultimate anode material for Li-based battery chemistries with high energy density. However, inhomogeneous charge distribution derived from the unbalanced ion/electron transport is usually generated at the electrode/electrolyte interface, leading to uncontrollable dendrite growth with poor reversibility. Herein, a mixed ionic/electronic conductive (MIEC) interlayer activated from the in situ conversion and nano-alloying reactions between the sputtered AlN arrays and metallic Li is efficiently constructed on the Li surface via facile mechanical calendaring. The 3D interconnected polyimide scaffolds with the extensive Li3N/Li9Al4 dual-decoration promote charge redistribution while enhancing electrochemical kinetics. The significantly reduced nucleation/plateau overpotentials, the overwhelming bottom-up lithium growth pattern derived from the tidal MIEC interlayer, combined with the inorganics-dominating solid electrolyte interphase synergistically regulates the uniform Li nucleation/growth. As demonstrated, a prolonged lifespan of the symmetric cell over 7500 h with an ultralow polarization of 12 mV is achieved at 5 mA cm⁻²@5 mAh cm⁻², further improving the rate capability and cycling performance of LiFePO4-based practical full cells with a capacity retention of 85.4% after 220 cycles. The proposed approach is also applicable to match the roll-to-roll production process, presenting an efficient strategy to realize the high-performance composite anode of industry-adaptable potential.