Carbon hollow spheres as electrochemical capacitors: Mechanistic insights

Insight into the Supercapacitive Behavior of Activated Hollow Porous Carbon Spheres in Different Electrolytes

“…To determine the SSA and porous structure of the AHPCSs, the nitrogen adsorption–desorption isotherm was measured. As depicted in Figure a, the nitrogen adsorption/desorption isotherm can be obviously regarded as a hybrid IUPAC type I and type IV curve, which reveals a combination of microporous, mesoporous, and macroporous structures. , The early stage ( P / P 0 < 0.05) of the isotherm with the sharp increase corresponds to a considerable amount of micropore filling, while the sloppy region at high relatively pressure ( P / P 0 > 0.95) indicates the presence of hollow macropores. Besides, it is generally known that an isotherm with a pronounced capillary condensation step at the medium relative pressure region manifests the multilayer adsorption on the mesopores, which can be observed in the curve of AHPCSs. − Furthermore, as depicted in Figure b, the PSD of the as-prepared AHPCSs illustrates that the activation of KOH will dramatically affect the PSD, which concentrates on the range from 1.23 to 4.50 nm including abundant micropores and mesopores.…”

“…As depicted in Figure 1a, the nitrogen adsorption/ desorption isotherm can be obviously regarded as a hybrid IUPAC type I and type IV curve, which reveals a combination of microporous, mesoporous, and macroporous structures. 30,31 The early stage (P/P 0 < 0.05) of the isotherm with the sharp increase corresponds to a considerable amount of micropore filling, while the sloppy region at high relatively pressure (P/P 0 > 0.95) indicates the presence of hollow macropores. Besides, it is generally known that an isotherm with a pronounced capillary condensation step at the medium relative pressure region manifests the multilayer adsorption on the mesopores, which can be observed in the curve of AHPCSs.…”

Synthesis of a Nickel Single-Atom Catalyst Based on Ni–N4–xCx Active Sites for Highly Efficient CO2 Reduction Utilizing a Gas Diffusion Electrode

“…To examine the effect of pyrolysis temperature on the carbon framework, the XPS C 1s spectrum is deconvoluted for C800NiA, C900NiA, and C1000NiA as shown in Figure S8 in the Supporting Information and results are tabulated in Table S3 in the Supporting Information. The XPS spectrum in Figure S8 in the Supporting Information reveals that the amount of graphitic sp 2 carbon content at 284.6 eV increases with temperature while sp 3 , C–O, and OC–O contents at 285.8, 286.8, and 288.6 eV, respectively, decreased. The presence of single-atom Ni is further characterized using NEXAFS analysis as shown in Figure b,c.…”

Hoya-like Hierarchical Porous Architecture as Multifunctional Phosphorus Anode for Superior Lithium–Sodium Storage

“…Among various RP hosts, hollow spheres with functional thin shells and large interior void space own the advantages of short ion diffusion paths, easy electrolyte penetration, and abundant active sites to boost electrochemical activity. − Once the active materials are filled into the internal cavity, the hollow shell with a negative radius of curvature can act as a gate to physically block them and provide extra space to perfectly mitigate the volumetric variation. , However, most of the available hollow spheres have relatively single configurations, such as a simple pore-type of one composition, which induces the serious agglomeration of bulk RP residing in the inner void, increasing the resistance of solid-state diffusion . Simplex physical constraints between the porous host and active species are not sufficient to maintain the cycle stability during electrochemical reactions due to the dissolution of polyphosphides. , In addition, one insurmountable hurdle faced by the hollow shell is that the RP deposited on the external surface would be easily detached from the conductive matrix .…”