Combined effect of nitrogen-doped functional groups and porosity of porous carbons on electrochemical performance of supercapacitors

Abstract

In this work, nitrogen-doped porous carbons obtained from chitosan, gelatine, and green algae were investigated in their role as supercapacitor electrodes. The effects of three factors on electrochemical performance have been studied—of the specific surface area, functional groups, and a porous structure. Varying nitrogen contents (from 5.46 to 10.08 wt.%) and specific surface areas (from 532 to 1095 m2 g−1) were obtained by modifying the carbon precursor and the carbonization temperature. Doping nitrogen into carbon at a level of 5.74–7.09 wt.% appears to be the optimum for obtaining high electrochemical capacitance. The obtained carbons exhibited high capacitance (231 F g−1 at 0.1 A g−1) and cycle durability in a 0.2 mol L−1 K2SO4 electrolyte. Capacitance retention was equal to 91% at 5 A g−1 after 10,000 chronopotentiometry cycles. An analysis of electrochemical behaviour reveals the influence that nitrogen functional groups have on pseudocapacitance. While quaternary-N and pyrrolic-N nitrogen groups have an enhancing effect, due to the presence of a positive charge and thus improved electron transfer at high current loads, the most important functional group affecting energy storage performance is graphite-N/quaternary-N. The study points out that the search for the most favourable organic precursors is as important as the process of converting precursors to carbon-based electrode materials.

Sono‐exfoliated graphene‐like activated carbon from hazelnut shells for flexible supercapacitors

“…From the XPS analysis, it was confirmed that the prepared samples mainly consisted of oxygen functional groups with trace amounts of nitrogen functionalities on the carbon framework. It is generally observed that activated carbon with O, N‐ heteroatoms play a positive role in providing additional pseudocapacitance, hydrophilicity, and promotes electron transfer rate of the electrode material 67,75,76 …”

“…It is generally observed that activated carbon with O, N-heteroatoms play a positive role in providing additional pseudocapacitance, hydrophilicity, and promotes electron transfer rate of the electrode material. 67,75,76…”

A Simple Route to Produce Highly Efficient Porous Carbons Recycled from Tea Waste for High-Performance Symmetric Supercapacitor Electrodes

“…The above set of results suggests that TAC3 has various O-containing and N-containing groups on the surface. Importantly, these functional groups can effectively improve the hydrophilicity and wettability of activated carbon, thus making the surface accessible to aqueous electrolytes and capable of excellent electrochemical performances [ 53 , 54 , 55 ].…”

Hydrothermal nitrogen doping of anthracene oil-derived activated carbons for wide voltage asymmetric capacitors

“…Reports on the use of N-doped ACs as active electrode materials for aqueous SCs show capacitance values between 150 and 250 F g − 1 , depending on the nitrogen content of the AC, the applied current densities and the electrolyte selected [8,12,[23][24][25]. However, in symmetric devices, the relatively high C sp values achieved do not improve to a high extent the energy and power densities.…”