Hybrid symmetric supercapacitor assembled by renewable corn silks based porous carbon and redox-active electrolytes

• Published in: Materials chemistry and physics 2018-10, Vol.218, p.229-238
• Main Authors: Sun, Kanjun, Zhang, Zhiguo, Peng, Hui, Zhao, Guohu, Ma, Guofu, Lei, Ziqiang
• Format: Article
• Language: English
• Subjects: Activated carbon; Agricultural wastes; Alizarin; Alizarin red; Aqueous solutions; Biomass; Biomass carbon; Bromoamine acid; Capacitance; Carbon; Corn; Density; Electrodes; Electrolytes; Energy storage; Flux density; Raw materials; Sulfuric acid; Supercapacitor; Supercapacitors; Weight; Zinc chloride
• ISSN: 0254-0584; 1879-3312
• DOI: 10.1016/j.matchemphys.2018.07.052

We have prepared nitrogen doped biomass activated carbon (CSC-1) using the agricultural wastes corn silks as raw materials and ZnCl2 as activating agent (the same weight of corn silks and ZnCl2) carbonized at 800 °C. The activated carbon has high specific surface areas of 1764.8 m2 g−1, large specific capacitance of 358.0 F g−1 at 0.5 A g−1, 67% of the capacitance retention at 20 A g−1, and 99.2% of initiatory specific capacitance after 5000 consecutive cycles. To improve the energy density of the symmetric supercapacitor based on CSC-1 electrodes, we employed the 1 M H2SO4 aqueous solution with alizarin red (AR) and bromoamine acid (ABA) as an advanced electrolyte to fabricate a novel hybrid symmetric cell. Surprisingly, the above device obtains a high specific capacitance of 260.8 F g−1 and a high energy density of 17.8 Wh kg−1, which are markedly higher than those in the conventional electrolyte. The improved energy storage is attributed to Faradaic pseudocapacitance related to the redox-active species of AR and ABA in the H2SO4 electrolyte. Based on the excellent characteristics, the device is expected as a promising candidate to fabricate high performance supercapacitors. •Nitrogen-doped porous carbon derived from a renewable corn silks.•The CSC-1 displays high specific surface area and large specific capacitance.•The alizarin red (AR) and bromoamine acid (ABA) are employed as redox-active species.•The hybrid symmetric supercapacitor exhibit high energy density and cyclic stability. [Display omitted]