Engineered heat dissipation and current distribution boron nitride-graphene layer coated on polypropylene separator for high performance lithium metal battery

• Published in: Journal of colloid and interface science Vol. 583; pp. 362 - 370
• Main Authors: Rodriguez, Jassiel R., Kim, Patrick J., Kim, Kyungho, Qi, Zhimin, Wang, Haiyan, Pol, Vilas G.
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-02-2021
• Subjects: Bilayer BNxGry/PP separator; Li metal battery; Superior performance; Suppression of dendritic Li; Synergistic effect; Bilayer BNxGry/PP separator; Suppression of dendritic Li; Li metal battery; Synergistic effect; Superior performance
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2020.09.009

The bilayer BNxGry/PP separator deliver a superior performance as result of an effective synergistic effect between physico-chemical properties of Gr and BN.
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•A BNxGry layer on one side of PP separator suppresses the sharp Li dendrite growth.•The bilayer BNxGry/PP separator improves the half- and full-cell performances.•Full cells with modified BN50Gr50/PP separator deliver 114 mAh g−1 at 1 C after 1000 cycles.
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 (BNxGry) 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.