Study on Preparation of Nitrogen-Doped Hierarchically Porous and High-Performance Carbon Materials from Seaweed Biomass

Abstract

Use Enteromorpha clathrate as a carbon and nitrogen precursor could obtain the N-doped porous carbon materials by two-step pyrolysis. In this paper, the exogenous nitrogen (urea, melamine) and activating agents (KOH, ZnCl 2 ) were employed for the production of higher-performance carbon materials from seaweed biomass. SEM, BET, FTIR, XRD, XPS, Raman and ultimate analyses were carried out to investigate the morpho-structural and elemental peculiarities of the carbonaceous materials. Moreover, cyclic voltammetry (CV) , galvanostatic chargedischarge (GCD) and cyclic charge-discharge tests were carried out to examine the electrochemical properties of the samples. The results showed that electrochemical performance of the carbonaceous materials improved by adding the appropriate nitrogen sources. This improvement was observed under either condition, when the nitrogen source and activating agent were melamine and ZnCl 2 or urea and KOH, respectively. Specifically, under the condition with KOH as the activator, the nitrogen content of carbon material without exogenous nitrogen was initially 1.46%. After the addition of urea or melamine, the nitrogen content increased to 4.86% and 6.18%, respectively. Under the condition with ZnCl 2 as the activator, and without exogenous nitrogen, the nitrogen content of carbon materials was initially 3.75%. However, after adding urea or melamine, the nitrogen content increased to 12.11% and 14.76%, respectively. The carbonaceous materials (prepared from urea/KOH and melamine/ZnCl 2 ) showed excellent gravimetric capacitances of 172 and 151.5 F/g at 1A/g. Moreover, at a current density of 5 A/g, their specific capacitance retention rate reached 78.3% and 82.6% respectively after 1000 cycles.

Facile Synthesis of Sustainable Biomass-Derived Porous Biochars as Promising Electrode Materials for High-Performance Supercapacitor Applications

“…The presence of more functionalities on the ZnCl 2 biochar surface can be related to the different activation mechanisms previously discussed. The existence of a high number of functional groups on biochar surfaces is often related to better electrochemical properties since it increases the electrode–electrolyte interactions [ 2 , 13 , 14 ].…”

“…Therefore, it is important to study new ways of replacing these high-cost and complex materials for cheaper and sustainable ones [ 2 , 3 , 12 , 13 , 14 ]. Extensive research is being conducted to develop innovative concepts using biomass materials as precursors to develop biochar-based materials employed as electrodes for SC [ 2 , 3 , 14 ].…”

“…The activation incorporates graphite nitrogen and pyridine nitrogen, resulting in the enhancement of the oxygen adsorption/ reduction, with direct consequences on the electron transfer. In particular, high pyridine-nitrogen content is an important requisite to reach adequate conditions in terms of good mesoporosity and pseudocapacitive contribution [ 13 ].…”

“…Basic research is required to optimize the production of electrodes adapted to the size of the electrolyte ions, thereby providing high conductivity and good physio-chemical stability that improve the electrochemical performance of biochar-based SCs (e.g., lifetime, capacity, and safety) [ 2 , 3 , 13 , 14 ].…”