High Capacitive Energy Storage of Nest‐Like Porous Graphene Microspheres Electrode with High Mass Loading

Abstract

Nest‐like porous graphene microspheres (NPGMs) are grown by using a chemical vapor deposition (CVD) method in a fluidized bed reactor from methane and basic magnesium carbonate microspheres (synthesized by a stirring‐induced crystallization approach) as carbon source and template, respectively. The CVD‐derived NPGMs have a few‐layer structure and high electrical conductivity, as well as a three‐dimensional individual macroarchitecture accompanied with well‐developed pore channels and great structural integrity. As the electrode for a symmetric supercapacitor, the effect of different mass loadings for NPGMs‐based electrodes on the capacitive energy‐storage performance is investigated. Superior electrochemical properties with respect to gravimetric, areal, and total capacitances, rate capability, and durability are shown by the NPGMs‐based symmetric supercapacitors, even at mass loadings up to 10 mg cm−2. Moreover, the electrochemical behavior of the NPGMs‐based electrode is much superior to those of two‐dimensional lamella‐like graphene and commercial activated carbon.

The Mass-Balancing between Positive and Negative Electrodes for Optimizing Energy Density of Supercapacitors

“…Data on the gravimetric specific capacitance of some electrode materials in different mass-loadings reported in the literature ,− are collected and listed in Table S1, and corresponding relations between the specific capacitance and the mass-loading are also shown in Figure . Obviously, it is shown that (1) the specific capacitance decreases with increasing the mass-loadings, while the decreasing degree in the low mass-loading range is much larger than in the high mass-loading range; (2) the change tendency is seemingly uncorrelated to the storage energy mechanisms of the materials together with electrolytes, but for some PC materials the mass-loading effect is more prominent; and (3) measured values of the specific capacitance depend on the current density and scan rate especially at high mass-loadings.…”

Exfoliating Waste Biomass into Porous Carbon with Multi-Structural Levels for Dual Energy Storage

“…Besides, this structure also allows disordered ions to travel through it efficiently under highloading conditions. 20 Fu et al prepared pore-rich and superwetted N/O/B triple-doped 2D carbon nanosheets using waste sweet potato leaves and boric acid (B 1 -SC), and the material exhibited a good specific capacitance of 296 F g −1 at 0.5 A g −1 in SCs. 21 Even with the addition of heteroatoms and a 2D, ultra-thin, and super-hydrophilic porous structure, the device is still prone to material stacking and collapses during operation, leaving poor electrochemical performance.…”

“…The open 3D porous structure provides not only high SSA and abundance of quadratic active sites but also a big ion electrode/electrolyte contact interface and low impedance, which can significantly increase energy density. Besides, this structure also allows disordered ions to travel through it efficiently under high-loading conditions . Fu et al prepared pore-rich and super-wetted N/O/B triple-doped 2D carbon nanosheets using waste sweet potato leaves and boric acid (B 1 -SC), and the material exhibited a good specific capacitance of 296 F g –1 at 0.5 A g –1 in SCs .…”