Effect of H₂SO₄/H₂O₂ pre-treatment on electrochemical properties of exfoliated graphite prepared by an electro-exfoliation method

Abstract

Early expansion of graphite after H2SO4/H2O2 pre-treatment and cyclic voltammograms of exfoliated graphite (EG) prepared with various volume fractions of H2O2.

Structural Modulation of Exfoliated Graphene via a Facile Postultrasonication Treatment toward Enhanced Electrochemical Properties of Supercapacitor Electrode

“…These results show that the specific EG capacitance increased as a higher ultrasonication power was applied during synthesis, owing to the higher surface area. A higher surface area generates a larger electroactive area to store the ions, which caused an increasing electrode capacitance. , However, EG 720 has a lower specific capacitance than EG 480 due to its lower surface area, as determined from the BET measurement. The rate capability of the prepared electrodes was measured at various current densities, and the results are depicted in Figure S5.…”

“…Before the electrochemical exfoliation process, graphite sheet as the precursor was dipped in the H 2 SO 4 / H 2 O 2 mixture for 3 min at ∼25 °C following the procedure in our previous work. 12 The solution was made by mixing 38 mL of concentrated H 2 SO 4 (96 wt %) and 2 mL of H 2 O 2 (50 wt %) for 5 min to obtain the H 2 SO 4 /H 2 O 2 mixture with a mole ratio of 95:5. After 5 min, the dipped graphite sheet was lifted from the H 2 SO 4 / H 2 O 2 mixture and let hang for 10 min.…”

“…9−11 Meanwhile, its large surface area makes this material show a higher specific capacitance than graphite, which has fewer accessible surfaces for ionic adsorption. 12 Therefore, to obtain the best performance of a graphene-based supercapacitor, it is necessary to enhance the electrical properties and increase the surface area of graphene.…”

“…Two factors that are mainly affecting the performance of supercapacitors are electrical conductivity and surface area. The high electrical conductivity of the graphene facilitates fast electron transport at the electrodes and contributes to the excellent specific capacitance and rate capability of the supercapacitor. − Meanwhile, its large surface area makes this material show a higher specific capacitance than graphite, which has fewer accessible surfaces for ionic adsorption . Therefore, to obtain the best performance of a graphene-based supercapacitor, it is necessary to enhance the electrical properties and increase the surface area of graphene.…”

Novel strategy for high-performance supercapacitors through the polyvinylpyrrolidone (PVP)-assisted in situ growth of FeS2

“…This indicated that FeS 2 had better conductivity or electron mobility in the sample after 3 wt% PVP addition. 61,62 The R ct value increased due to the higher dead mass that was wrapped around the active material sites, increasing the resistance at high PVP concentration.…”