Thin Film Materials Laboratory, Department of Physics, Shivaji University, Kolhapur 416004, India.
School of Materials Science and Innovation, Faculty of Science, Mahidol University, Bangkok, Thailand.
J Colloid Interface Sci. 2018 Oct 1;527:40-48. doi: 10.1016/j.jcis.2018.05.022. Epub 2018 May 11.
Symmetric supercapacitor is advanced over simple supercapacitor device due to their stability over a large potential window and high energy density. Graphene is a desired candidate for supercapacitor application since it has a high surface area, good electronic conductivity and high electro chemical stability. There is a pragmatic use of ionic liquid electrolyte for supercapacitor due to its stability over a large potential window, good ionic conductivity and eco-friendly nature. For high performance supercapacitor, the interaction between ionic liquid electrolyte and graphene are crucial for better charge transportation. In respect of this, a three-dimensional (3D) nanoporous honeycomb shaped sulfur embedded graphene (S-graphene) has been synthesized by simple chemical method. Here, the fabrication of high performance symmetric supercapacitor is done by using S-graphene as an electrode and [BMIM-PF] as an electrolyte. The particular architecture of S-graphene benefited to reduce the ion diffusion resistance, providing the large surface area for charge transportation and efficient charge storage. The S-graphene and ionic liquid-based symmetric supercapacitor device showed the large potential window of 3.2 V with high energy density 124 Wh kg at 0.2 A g constant applied current density. Furthermore, this device shows good cycling performance (stability) with a capacitive retention of 95% over 20,000 cycles at a higher current density of 2 A g.
对称超级电容器优于简单超级电容器，因为它们具有较大的电位窗口和较高的能量密度稳定性。由于具有较大的比表面积、良好的电子导电性和较高的电化学稳定性，石墨烯是超级电容器应用的理想候选材料。由于其在较大的电位窗口内具有稳定性、良好的离子导电性和环保特性，因此离子液体电解质在超级电容器中有实际应用。对于高性能超级电容器，离子液体电解质与石墨烯之间的相互作用对于更好的电荷传输至关重要。在这方面，通过简单的化学方法合成了三维（3D）纳米多孔蜂窝状硫嵌入石墨烯（S-石墨烯）。在这里，使用 S-石墨烯作为电极和[BMIM-PF]作为电解质来制造高性能对称超级电容器。S-石墨烯的特殊结构有利于降低离子扩散阻力，为电荷传输提供大的表面积和有效的电荷存储。S-石墨烯和基于离子液体的对称超级电容器器件具有 3.2 V 的大电位窗口，在 0.2 A g 的恒定施加电流密度下具有 124 Wh kg 的高能量密度。此外，该器件在较高电流密度为 2 A g 时具有良好的循环性能（稳定性），在 20,000 次循环后电容保持率为 95%。
