Abstract The two-dimensional hexagonal boron nitride (h-BN) has garnered tremendous interest due to its unique mechanical, thermal and electronic properties. However, the application of h-BN has been restricted as electrode materials for supercapacitors because of its wide band gap and rather low conductivity. Herein, a carbon-modified hexagonal boron nitride nanosheet (h-BN/C) nanocomposite is prepared through a facile and scalable solid-state reaction. Interestingly, the h-BN/C nanocomposite as cathode material exhibits a pair of distinct and reversible redox peaks in 2 M KOH aqueous electrolyte. Because of the enhanced electrical conductivity derived from the modified carbon and the increased specific surface area, the h-BN/C nanocomposite presents a high specific capacitance of 250 F g−1 at the current density of 0.5 A g−1. More importantly, the fabricated aqueous asymmetric supercapacitor with the h-BN/C as cathode and activated carbon as anode displays an operating voltage of 1.45 V, an energy density of 17 Wh kg−1 at a power density of 245 W kg−1, and high stability up to 1000 cycles. Therefore, h-BN/C nanocomposite would promisingly be a cathode material for aqueous asymmetric supercapacitors.

中文翻译：

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六方氮化硼纳米片/碳纳米复合材料作为高性能正极材料用于水不对称超级电容器

摘要 二维六方氮化硼（h-BN）由于其独特的机械、热和电子特性而引起了极大的兴趣。然而，h-BN由于其宽带隙和相当低的电导率而限制了其作为超级电容器电极材料的应用。在此，通过简便且可扩展的固态反应制备了碳改性的六方氮化硼纳米片 (h-BN/C) 纳米复合材料。有趣的是，作为正极材料的 h-BN/C 纳米复合材料在 2 M KOH 水性电解质中表现出一对明显且可逆的氧化还原峰。由于改性碳带来的增强的导电性和增加的比表面积，h-BN/C 纳米复合材料在 0.5 A g-1 的电流密度下呈现出 250 F g-1 的高比电容。更重要的是，以 h-BN/C 为阴极，活性炭为阳极，制备的水性非对称超级电容器的工作电压为 1.45 V，能量密度为 17 Wh kg-1，功率密度为 245 W kg-1，并且稳定性高高达 1000 次循环。因此，h-BN/C 纳米复合材料有望成为水性非对称超级电容器的正极材料。