Interfacial ion-redistribution via lithiophilic-lithiophobic/insulating-conductive dual-gradient design for uniform and controllable lithium deposition

The practical implementation of high-energy-density lithium metal batteries is significantly hindered by the dendrite growth stemming from inhomogeneous lithium deposition at the anode, particularly under high current densities. Achieving a long-term stable lithium metal anode remains a substantial challenge. This work proposes a functionalized anode current collector (PZ@CF) exhibiting a dual-gradient effect. Through a progressive design incorporating a zinc metal layer and a PVDF layer, a gradient structure integrating lithiophilic-lithiophobic and conductive-insulating characteristics is constructed. This design synergistically modulates the electric field distribution, lithium-ion flux, and local current density, inducing bottom-up uniform lithium deposition and effectively suppressing volume expansion and dendrite growth on the lithium metal anode. Experimental results demonstrate that half-cells employing the PZ@CF current collector achieve stable cycling for 360 cycles at 1 mA cm⁻² and 1 mAh cm⁻², with a high average Coulombic efficiency of 97.76 %. Asymmetric cells exhibit a cycling lifespan exceeding 700 h at 2 mA cm⁻². Furthermore, PZ@CF/Li||NCM full cells maintain a capacity retention of 90 % after 100 cycles. These performances are significantly superior to those achieved with non-gradient or bare copper foam current collectors. This study provides a novel design strategy for current collectors toward highly stable lithium metal anodes.