“Water-in-salt” electrolyte enhanced high voltage aqueous supercapacitor with carbon electrodes derived from biomass waste-ground grain hulls

Abstract

To design high specific surface area and optimize the pore size distribution of materials, we employ a combination of carbonization and KOH activation to prepare activated carbon derived from ground grain hulls.

Development of a Novel Bio‐based Redox Electrolyte using Pivalic Acid and Ascorbic Acid for the Activated Carbon‐based Supercapacitor Fabrication

“…Non‐aqueous solvent‐based organic electrolytes (OEs) and ILs have shown to significantly improve the performance of supercapacitors. OEs‐ and ILs‐based supercapacitors can easily obtain a large potential window of 2–3 V and 3–5 V, respectively [13–15] . However, OEs typically suffer from flammability, volatility, and toxicity; and most importantly, sluggish ion diffusion is usual for their high viscosity.…”

“…Aqueous electrolytic systems are preferable because of their high ionic conductivity, non‐volatility, non‐flammability, and cost effectiveness. Nevertheless, their narrow operating potential window (OPW) is limited due to hydrogen and oxygen evolution reactions, thus, having low energy densities [14,17,18] . In many cases, preconditioning of an aqueous electrolyte in its highly pure state is not facile for large‐scale applications in supercapacitors.…”

“…Nevertheless, their narrow operating potential window (OPW) is limited due to hydrogen and oxygen evolution reactions, thus, having low energy densities. [14,17,18] In many cases, preconditioning of an aqueous electrolyte in its highly pure state is not facile for large-scale applications in supercapacitors. This is one of the reasons why the search for available and efficient aqueous electrolytes for supercapacitors has gained significant attention.…”

“…OEs-and ILsbased supercapacitors can easily obtain a large potential window of 2-3 V and 3-5 V, respectively. [13][14][15] However, OEs typically suffer from flammability, volatility, and toxicity; and most importantly, sluggish ion diffusion is usual for their high viscosity. Although ILs can overcome such limitations, the limited availability and expensiveness of ILs have restricted their further application in supercapacitors.…”

Nelumbo nucifera Seed–Derived Nitrogen-Doped Hierarchically Porous Carbons as Electrode Materials for High-Performance Supercapacitors

“…The biochar can be further activated by mixing with chemical activating agents such as KOH, zinc chloride, and phosphoric acid and carbonized at higher temperatures (up to 1000 • C) to enhance the porosity and the specific surface area. Several biomass-derived nanoporous carbons have been reported to show high surface area above 2000 m 2 g −1 , depending on the precursor itself, carbonization temperature, chemical activating agent and mixing ratio with the activating agent [41][42][43][44][45][46]. Due to high surface area and well-developed porosity, the biomass carbons perform excellently as the electrode materials for the electrochemical supercapacitors.…”