Li metal as a battery anode has been intensively studied because of its high gravimetric capacity (3860 mAh g⁻¹), a low standard electrode potential (−3.04 vs. SHE), a reasonable electronic conductivity and low density. However, lithium metal suffers from a continuous Li dendrite growth upon charge-discharge cycling, delivering a poor coulombic efficiency and consequently its early failure. Here, engineered bilayer separators demonstrate that a boron nitride-graphene (BN_xGr_y) layer coated on one side of polypropylene (PP) membrane remarkably reduces the polarization and impedance, and significantly improve the performance and stability of Li/Cu half-cells. Moreover, Li/LiFePO₄ full cell with the modified BN₅₀Gr₅₀/PP separator presents a remarkably stable 1000 charge-discharge cycles with a specific capacity of 114 mAh g⁻¹ at 1C-rate. The superiority of the modified separator is orginated from an effective synergistic effect between physico-chemical properties of Gr (reducing local current density) and BN (dissipating local heat) and its enhanced structural and mechanical stability.

由于锂金属的重量容量高（3860 mAh g ^-1），标准电极电位低（相对于SHE为-3.04），合理的电子电导率和低密度，因此对其进行了深入研究。然而，锂金属在充放电循环中遭受连续的Li枝状晶体生长，库伦效率低，因此其早期失效。在这里，经过工程学设计的双层隔膜证明，涂在聚丙烯（PP）膜一侧的氮化硼-石墨烯（BN _x Gr _y）层显着降低了极化和阻抗，并显着提高了Li / Cu半电池的性能和稳定性。此外，Li / LiFePO ₄全电池具有改进的BN ₅₀Gr ₅₀ / PP隔膜在1C速率下表现出非常稳定的1000次充放电循环，比容量为114 mAh g ^-1。改性隔板的优越性源于Gr（降低局部电流密度）和BN（耗散局部热量）的物理化学性质及其增强的结构和机械稳定性之间的有效协同作用。