Hierarchical Porous Carbon Derived from Sichuan Pepper for High-Performance Symmetric Supercapacitor with Decent Rate Capability and Cycling Stability

Abstract

Hierarchical micro-mesoporous carbon (denoted as HPC-2 in this study) was synthesized by pre-carbonization of biomass Sichuan pepper followed by KOH activation. It possessed well-developed porosity with the specific surface area of 1823.1 m2 g−1 and pore volume of 0.906 cm3 g−1, and exhibited impressive supercapacitive behaviors. For example, the largest specific capacitance of HPC-2 was tested to be ca. 171 F g−1 in a three-electrode setup with outstanding rate capability and stable electrochemical property, whose capacitance retention was near 100% after cycling at rather a high current density of 40 A g−1 for up to 10,000 cycles. Furthermore, a two-electrode symmetric supercapacitor cell of HPC-2//HPC-2 was constructed, which delivered the maximum specific capacitance and energy density of ca. 30 F g−1 and 4.2 Wh kg−1, respectively, had prominent rate performance and cycling stability with negligible capacitance decay after repetitive charge/discharge at a high current density of 10 A g−1 for over 10,000 cycles. Such electrochemical properties of HPC-2 in both three- and two-electrode systems are superior or comparable to those of a great number of porous biomass carbon reported previously, hence making it a promising candidate for the development of high-performance energy storage devices.

A Microtubular Direct Carbon Solid Oxide Fuel Cell Operated on the Biochar Derived from Pepper Straw

“…Most notably, the amorphous carbon is more active to the Boudouard reaction compared with graphite. Consequently, the calculated I D / I G value of the pepper straw char is 0.98, which is close to the result of 0.94 in the previous literature, suggesting that the pepper straw can be considered as a good fuel for the microtubular DC‐SOFCs.…”

Homogeneous Core/Shell NiMoO4@NiMoO4 and Activated Carbon for High Performance Asymmetric Supercapacitor

“…The CV profiles were tested at a constant scan rate of 30 mV/s within various ranges of voltage (see Figure S3). The peak tail, which appears as a consequence of an undesirable oxygen evolution reaction-induced peak in the CV profiles when the voltage is broadened to 1.5 V or higher, indicates that the maximum working voltage of the ASC should be around 1.2 V. Such a phenomenon was explained in a similar way in the previous literatures [52,53,54]. For example, Xu et al reported that the optimized operating voltage range of the ZIF-LDH/GO//ZIF-C/G device was 0–1.6 V in order to avoid the oxygen evolution reaction at 1.6–1.8 V [55].…”

Naturally occurring neem gum: An unprecedented green resource for bioelectrochemical flexible energy storage device

“…The CV curves remain closely quasi-rectangular without apparent distortion even at a scan rate of 100 mV/s. As the scan rate enhances from 5-100 mV/s, the quasirectangular shape is well maintained, implying the EDLC capacitive behaviour of electrode material and speedy diffusion of electrolyte ions within the electrode 64,65 .…”