Rodriguez Jassiel R, Kim Patrick J, Kim Kyungho, Qi Zhimin, Wang Haiyan, Pol Vilas G
Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA.
Davidson School of Chemical Engineering, Purdue University, West Lafayette, IN 47907, USA.
J Colloid Interface Sci. 2021 Feb 1;583:362-370. doi: 10.1016/j.jcis.2020.09.009. Epub 2020 Sep 15.
Li metal as a battery anode has been intensively studied because of its high gravimetric capacity (3860 mAh g), 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 (BNGr) 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/LiFePO full cell with the modified BNGr/PP separator presents a remarkably stable 1000 charge-discharge cycles with a specific capacity of 114 mAh g 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.
锂金属作为电池阳极，因其高比容量（3860 mAh g）、低标准电极电位（相对于标准氢电极-3.04 V）、合理的电子导电性和低密度而受到广泛研究。然而，锂金属在充放电循环过程中会持续生长锂枝晶，导致库仑效率低下，最终导致电池过早失效。在此，工程化双层隔膜表明，涂覆在聚丙烯（PP）膜一侧的氮化硼-石墨烯（BNGr）层显著降低了极化和阻抗，并显著提高了锂/铜半电池的性能和稳定性。此外，采用改性BNGr/PP隔膜的锂/磷酸铁锂全电池在1C倍率下呈现出显著稳定的1000次充放电循环，比容量为114 mAh g。改性隔膜的优势源于石墨烯（降低局部电流密度）和氮化硼（耗散局部热量）的物理化学性质之间的有效协同效应及其增强的结构和机械稳定性。
