Oil tea shell derived porous carbon with an extremely large specific surface area and modification with MnO2 for high-performance supercapacitor electrodes. (June 2017)

• Record Type: Journal Article
• Authors: Zhou, Meng; Gomez, Joshua; Li, Binsong; Jiang, Ying-Bing; Deng, Shuguang
• Is Part Of: Applied materials today. Volume 7(2017)
• Page Start: 47
• Page End: 54
• Publication Date: 2017-06
• Subjects: MnO2 -- Activated carbon -- Rate capability -- Cycle stability -- Energy density; Materials science -- Periodicals; Materials -- Research -- Periodicals; 620.1105
• DOI: 10.1016/j.apmt.2017.01.008
• Languages: English
• ISSNs: 2352-9407

Abstract

Graphical abstract: Highlights: Oil tea shell derived carbon electrode with a BET of 2851 m 2 /g and pore volume of 2.68 cm 3 /g. MnO2 /carbon electrode has a specific capacitance of 1126 F/g @ 0.5 A/g. A two-electrode supercapacitor cell showed an energy density of 24 Wh/kg and a power density of 275 W/kg. Abstract: Activated carbon (AC) with an extremely large specific surface area (2851 m 2 /g) and large pore volume (2.68 cm 3 /g) was derived from bio-waste oil tea shells by using ZnCl2 as the activation agent. The porous carbon had a high amount of CO2 adsorption (3.61 mmol/g) at ambient conditions (25 °C, 1 bar). Comprehensive characterizations including XRD, Raman, SEM, TEM, and TGA proved graphite existed in the AC samples. However, the capacitance (146 F/g @ 0.5 A/g) was in the normal range of carbon materials. By coating with a thin layer of MnO2, the capacitance of MnO2 /AC was enhanced significantly (1126 F/g @ 0.5 A/g) without sacrificing the rate capability and cycle stability, even though the surface area was reduced to 23 m 2 /g and pore volume reduced to 0.05 cm 3 /g. A two-electrode (MnO2 /AC//AC) supercapacitor cell was set up, the energy density reached 24 Wh/kg with a power density of 275 W/kg.