Zainab Sana, Fraz Sajal, Awan Saif Ullah, Hussain Danish, Rizwan Syed, Mehmood Waqar
Department of Electrical Engineering, NUST College of Electrical and Mechanical Engineering, National University of Sciences and Technology (NUST), Islamabad, 54000, Pakistan.
Department of Mechatronics Engineering, NUST College of Electrical and Mechanical Engineering, National University of Sciences and Technology (NUST), Islamabad, 54000, Pakistan.
Sci Rep. 2023 Aug 30;13(1):14218. doi: 10.1038/s41598-023-41309-9.
High capacitance devices (Supercapacitors) fabricated using two-dimensional materials such as Graphene and its composites are attracting great attention of the research community, recently. Synthesis of 2D materials and their composites with high quality is desirable for the fabrication of 2D materials-based supercapacitors. Ultrasonic Assisted Liquid Phase Exfoliation (UALPE) is one of the widely used techniques for the synthesis of graphene. In this article, we report the effect of variation in sonication time on the exfoliation of graphite powder to extract a sample with optimal properties well suited for supercapacitors applications. Three different graphite powders (hereafter termed as sample A, sample B, and sample C) were sonicated for duration of 24 h, 48 h and 72 h at 60 °C. The exfoliation of graphite powder into graphene, GO and GrO was studied using XRD and RAMAN. AFM and SEM were further used to examine the layered structure of the synthesized nanocomposite. UV-visible spectroscopy and cyclic voltammetery were used to measure the band gaps, and capacitive behavior of the samples. Sample B exhibited a remarkable specific capacitance of 534.53 F/g with charge specific capacity of 530.1 C/g at 1 A/g and energy density of 66 kW/kg. Power density varied 0.75 kWh/kg to 7.5 kWh/kg for a variation in current density from 1 to 10 A/g. Sample B showed capacitive retention of 94%, the lowest impedance and highest degree of exfoliation and conductivity as compared to the other two samples.
最近，使用石墨烯等二维材料及其复合材料制造的高电容器件（超级电容器）引起了研究界的极大关注。高质量二维材料及其复合材料的合成对于制造基于二维材料的超级电容器是很有必要的。超声辅助液相剥离法（UALPE）是广泛用于合成石墨烯的技术之一。在本文中，我们报告了超声处理时间的变化对石墨粉剥离的影响，以提取具有最适合超级电容器应用的最佳性能的样品。三种不同的石墨粉（以下称为样品A、样品B和样品C）在60℃下分别超声处理24小时、48小时和72小时。使用XRD和拉曼光谱研究了石墨粉向石墨烯、氧化石墨烯和石墨氧化物的剥离情况。进一步使用原子力显微镜（AFM）和扫描电子显微镜（SEM）来检查合成的纳米复合材料的层状结构。使用紫外可见光谱和循环伏安法测量样品的带隙和电容行为。样品B在1A/g电流密度下表现出534.53F/g的显著比电容，电荷比容量为530.1C/g，能量密度为66kW/kg。当电流密度从1A/g变化到10A/g时，功率密度从0.75kWh/kg变化到7.5kWh/kg。与其他两个样品相比，样品B的电容保持率为94%，具有最低的阻抗、最高的剥离程度和电导率。
