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

Abstract

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

A collagen-based electrolyte-locked separator enables capacitor to have high safety and ionic conductivity

“…8 . It could be observed that the energy density was 10.1 Wh kg −1 at the power density of 500 W kg −1 , which was comparable with other EDLC reported [40][41][42][43][44] . The comparison of electrochemical performance between the present work and other works were summarized in Table 2 .…”

Green self-activating synthesis system for porous carbons: Celery biomass wastes as a typical case for CO2 uptake with kinetic, equilibrium and thermodynamic studies

“…3 (b)) show D-band peaks at approximately 1345 cm -1 and G-band peaks at around 1603 cm -1 , indicating the presence of a carbon lattice defect with a distorted structure (sp3) and some orderlayered graphite with vibration sp2 hybridized carbon atoms, respectively. Moreover, the presence of a 2D-band around 2873 (cm -1 ) is a sign of a local graphene-like structure [16,[59][60][61][62][63]. The integrated intensity ratio of the D and G bands (Id to Ig) can be used to evaluate the surface graphitization, higher of which shows lower graphitization level.…”

Green Self-Activating Synthesis System for Porous Carbons; Celery Biomass Wastes as a Typical Case for CO2 Uptake with Kinetic, Equilibrium and Thermodynamic Studies

“…3 (b)) show D-band peaks at approximately 1345 cm -1 and G-band peaks at around 1603 cm -1 , indicating the presence of a carbon lattice defect with a distorted structure (sp3) and some orderlayered graphite with vibration sp2 hybridized carbon atoms, respectively. Moreover, the presence of a 2D-band around 2873 (cm -1 ) is a sign of a local graphene-like structure [16,[59][60][61][62][63]. The integrated intensity ratio of the D and G bands (Id to Ig) can be used to evaluate the surface graphitization, higher of which shows lower graphitization level.…”