Synthesis of activated carbon nanospheres with hierarchical porous structure for high volumetric performance supercapacitors

Silica‐assisted urea‐formaldehyde‐based carbon microspheres with enhanced supercapacitor performances as electrode

“…EIS is used to further characterize the electrochemical properties of electrode materials based on their frequency response characteristics . As shown in Figure (c), the Nyquist curves of all carbon electrode have a straight line in the low‐frequency region owing to the existence of Warburg impedance, which presents the internal resistance of ion diffusion to the electrode interface in the electrolyte . In addition, the inset of Figure (c) shows an enlarged Nyquist curve in the high‐frequency region and the arc curve is related to the equivalent series resistance, a semicircle in the high frequency; the radius of the semicircular area indicates the conductivity of the electrode material and the charge transfer resistance in the electrode material, respectively.…”

Metal chloride-assisted synthesis of hierarchical porous carbons for high-rate-performance supercapacitor

“…The common methods of activation include physical activation and chemical activation. [30][31][32][33][34][35][36][37] The physical activation process involves carbonization of the raw materials and the subsequent activation at high temperature in a carbon dioxide or steam atmosphere. [35][36][37] In the chemical activation process, a series of cross-linking and pyrolysis processes could happen quickly at lower temperature to create abundant pores.…”

“…[35][36][37] In the chemical activation process, a series of cross-linking and pyrolysis processes could happen quickly at lower temperature to create abundant pores. [30][31][32][33][34] Recently, low melting point salts, such as ZnCl 2 , LiCl, KCl and NaCl, as activator, have been explored for the synthesis of porous materials with unique nanostructures. [38][39][40][41][42] Nevertheless, the typical activation reaction mainly carried out on the surface of materials, making it difficult to create appropriate and accessible pores in the bulk for ion diffusion and adsorption.…”

Dual-ion hybrid supercapacitor: Integration of Li-ion hybrid supercapacitor and dual-ion battery realized by porous graphitic carbon

“…In a DIB, anions undergo an intercalation/de-intercalation reaction into the positive electrode material, which requires the positive electrode to possess a crystalline layered structure, namely a high graphitization degree for a carbon-based material [9] . On the other hand, in a Li-HSC, anions undergo a physical adsorption/desorption reaction on the surface of the positive electrode material to form an electronic doublelayer capacitor (EDLC), which requires the positive electrode material to have a highly porous structure [5,10] ; (2) The potential of the positive electrode reaction. The intercalation/de-intercalation reaction in a DIB occurs at the high-potential range (4.0-5.0 V vs. Li/Li + ) [11] , while the EDLC behavior without Faraday reaction in the positive material occurs at a wide potential range [12] .…”