Thiosalicylic Acid Modified Graphene Aerogel as Efficient Electrode Material for Ionic Liquid Electrolyte-Based Supercapacitors

Balancing energy density and power density of supercapacitors is highly desired to extend their application range. The development of new electrode materials with efficient electron/ion migration channels and large surface area accessible by the ionic liquid (IL) electrolyte with high stable potential window is a critical way to construct the high-performances of supercapacitors. In this work, a thiosalicylic acid modified graphene aerogel (TGA) was prepared by hydrothermal treatment of a graphene oxide precursor using thiosalicylic acid (TSA) as reductant, sulfur-dopant, and modifier. As-prepared TGA material has hierarchically porous texture with wide pore size distribution range and large accessible surface area by IL electrolytes, which is beneficial to the rapid diffusion and adsorption of IL electrolyte ions with larger ion sizes and high viscosity. Therefore, the TGA material possesses high specific capacitance and rate capability. Using 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([Bmim][Tf2N]) IL electrolyte, the assembled symmetric TGA-based supercapacitor can deliver energy densities of 115–28 Wh kg–1 within power densities of 946–11586 W kg–1. The current work provides a feasible avenue to accomplish the balance between energy density and power density of supercapacitors via the design and synthesis of hierarchically porous graphene aerogels containing doped-heteroatoms and matching with IL electrolyte.