Tuning the electrochemical capacitance of carbon nanosheets by optimizing its thickness through controlling the carbon precursor in salt‐template

Abstract

Herein, two‐dimensional (2D) carbon nanosheets derived from biomass precursor is successfully synthesized via a cost‐effective salt‐templated process. Microstructural characterization and Raman spectral analysis of the sample derived from the salt template method reveals the formation of carbon nanosheets. The nanosheet thickness and its capacitance have been altered by varying the carbon precursor to salt‐template ratio. From the AFM data, the thickness of the as‐prepared thin carbon sheet was measured as ~5.16 nm, and the other thicker carbon sheet thickness was determined to be between 24 and 38 nm. The Brunauer Emmett Teller (BET) analysis shows that the thinner nanosheets possess a high specific surface area (SSA) of 485 m2 g−1, with slit‐pore geometry having a total pore volume of 0.29 cm3 g−1. Hence, compared to thicker carbon nanosheets (63.6 F g−1), the thinner carbon nanosheets exhibit superior electrochemical capacitance of 146 F g−1 in an aqueous 6 M KOH electrolyte, without employing any chemical activation. The electrochemical series resistance of as‐prepared carbon nanosheet samples was found to be <1 Ω with charge transfer resistances in the range of 0.29 Ω (thicker sheets) to 0.18 Ω (thinner sheets). The specific capacitance and electrochemical properties vary significantly when the nanosheet thickness has been tuned from thicker to thinner by altering the starch ratio in NaCl. The two‐electrode cell assembled using thinner carbon nanosheets exhibited the capacitance of 70.1 F g−1 with energy and power densities as 9.7 Wh kg−1 and 20 kW kg−1 respectively.

Electrochemical capacitance and hydrogen adsorption behavior of activated carbon derived from cattail fiber

“…For coin cell fabrication, Ni foam coated with electrode material (~6 mg) and 1 M Na 2 SO 4 (electrolyte) was used. The process adopted for the fabrication of coin cells has been described in our earlier paper 25 . The CV and GCD measurements of coin cells were performed for the potential window from 0 to 1.4 V and the electrochemical impedance spectrum was measured from 20 kHz to 100 mHz.…”

Salt-assisted synthesis of advanced carbon-based materials for energy-related applications

“…In addition, the symmetric supercapacitor device assembled using thinner carbon nanosheets had a capacitance of 70.1 F g −1 with energy and power densities of 9.7 W h kg −1 and 20 kW kg −1 , respectively. 179 Pramanik et al presented the synthesis of a composite comprising nanoscale discrete Mn 3 O 4 particles (20 nm) into a two-dimensional sheet-like N-incorporated mesoporous carbon using NaCl crystallites as an exo-template, which demonstrated excellent performance as anode for a lithium ion battery. 180…”

Porous Carbon Nanosheets Derived from Spent Coffee Grounds for Highly Stable Electric Double-Layer Capacitors Enabled by Structurally Complementary Carbons

“…This suggests that SCGs would be an ideal candidate for solid waste cycling. In addition, it has been reported that after carbonization and activation, SCGs can generate high-value two-dimensional (2D) porous carbon nanosheets (PCNs) − The interlinked hierarchical porous structure of the 2D PCNs, combined with the 2D framework and pore architectures, has a high specific surface area and porous channels, as well as good electrical conductivity, resulting in superior potential in energy-storage applications, especially in supercapacitors, ,,− lithium–sulfur batteries, − and metal–air batteries. − …”