Effect of KOH on the Energy Storage Performance of Molasses-Based Phosphorus and Nitrogen Co-Doped Carbon

Abstract

In this study, we have evaluated the effect of potassium hydroxide (KOH) on the energy storage performance of metal-free carbon-based materials prepared from molasses. Molasses are a renewable-resource biomass and economical by-product of sugar refinement, used here as a carbon precursor. Two co-doped carbon materials using molasses were synthesized via a time and cost-efficient microwave carbonization process, with ammonium polyphosphate as a phosphorus and nitrogen doping agent. The phosphorus and nitrogen co-doped carbon (PNDC) samples were prepared in the presence and absence of a chemical activating agent (KOH), to study the role of chemical activation on PNDCs. Physical characterizations were performed to gain insight into the composition, pore size and topographical data of each material. Electrochemical characterization via cyclic voltammetry in 1 M sulfuric acid (H2SO4) as well as in 6 M KOH as electrolytes, revealed high current density and specific capacitance for the chemically activated material (PNDC2) compared to one without chemical activation (PNDC1). The capacitance value of 244 F/g in KOH electrolyte was obtained with PNDC2. It is concluded that addition of KOH prior to carbonization increases the surface functionality, which significantly enhances the electrochemical properties of the PNDC material such as current density, stability, and specific capacitance.

A Review of Electrospun Carbon Nanofiber-Based Negative Electrode Materials for Supercapacitors

“…Moreover, carbon materials have desirable properties, such as a large surface area and outstanding conductivity, compared to metal-based electrodes. The major carbon materials are activated carbon (AC) [36,37], carbon nanotubes (CNTs) [38,39], graphene [40], carbon cloth (CC) [41], electrospun carbon nanofibers [32,42,43], porous carbons [44][45][46], and their composites (Table 1).…”

Characterization and Electrocatalytic Performance of Molasses Derived Co-Doped (P, N) and Tri-Doped (Si, P, N) Carbon for the ORR

“…In recent years, researchers have investigated the significance of doping amorphous carbon with heteroatoms in relation to the effect on its electrochemical properties [25,26]. This involves the introduction of a small number of defects into a carbon matrix.…”

“…This involves the introduction of a small number of defects into a carbon matrix. The doping of amorphous carbons with many different elements has been reported, such as with nitrogen, boron, sulfur, and phosphorus [25,27,28]. These atoms serve to change the properties of the material by altering the band gap, conductivity, and electrochemical characteristics [29].…”

“…Researchers also seek to determine the optimal doping elemental composition for electrocatalytic performance. This is achieved by doping with one, two, or even three different elements [25,30,31]. Phosphorus and nitrogen co-doping of carbon is often employed for energy storage applications such as fuel cell and supercapacitors [25,27].…”

“…This is achieved by doping with one, two, or even three different elements [25,30,31]. Phosphorus and nitrogen co-doping of carbon is often employed for energy storage applications such as fuel cell and supercapacitors [25,27]. Recently, it has been shown that introducing silicon with other heteroatoms such as nitrogen or phosphorus can enhance the ORR activity of carbon materials due to alteration in the charge distribution and energetic characteristics of the material [32].…”