Capacitive performance of porous carbon nanosheets derived from biomass cornstalk. Issue 2 (4th January 2017)

• Record Type: Journal Article
• Authors: Yu, Hang; Zhang, Wenliang; Li, Ting; Zhi, Lei; Dang, Liqin; Liu, Zonghuai; Lei, Zhibin
• Is Part Of: RSC advances. Volume 7:Issue 2(2017)
• Page Start: 1067
• Page End: 1074
• Publication Date: 2017-01-04
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c6ra25899a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Porous carbon nanosheets derived from naturally abundant cornstalk are reported as a high rate supercapacitor electrode in aqueous and solid-state PVA–KOH electrolyte. Abstract : Porous carbon nanosheets (aCS) formed by carbonization and chemical activation of biomass cornstalk are presented for capacitive energy storage. The obtained carbon possesses a two-dimensional (2D) sheet-like structure which is mainly composed of abundant micropores. Depending on the amount of KOH used in the activation step, the specific surface area of the carbon sheets varies from 388 to 1736 m 2 g −1, whereas the lateral size is in the range of 50–100 μm, and sheet thickness is around 100 nm. The capacitive performance of aCS-5 in both KOH and Na2 SO4 aqueous electrolytes is investigated. The aCS-5 electrode in KOH electrolyte exhibits a remarkable high-rate capability due to the dramatically shortened ion pathway and more exposed external surface. While, in Na2 SO4 it shows relatively lower capacitance retention but a stable and extended voltage window (0–1.6 V), thus delivering a specific energy of 20.2 W h kg −1 at a power density of 398 W kg −1 . The aCS-5 with a large aspect ratio (200–500) can also serve as an electrode for assembling a solid-state capacitor (SSC) using PVA/KOH gel as a polymer electrolyte. The SSC retains the normal capacitive performance under bent and twisted states and exhibit an unusual rate capability with an areal capacitance of 136 mF cm −2 at 0.5 mA cm −2 .