Battery-like supercapacitors from diamond networks and water-soluble redox electrolytes

Abstract

Battery-like supercapacitors fabricated with a 3D diamond network and water-soluble redox electrolytes exhibit large capacitances and high energy and power densities.

3D 3C‐SiC/Graphene Hybrid Nanolaminate Films for High‐Performance Supercapacitors

“…SCs store energy in two ways: either via reversible electrostatic charge accumulation at the electrode/electrolyte interface (so‐called electric double layer capacitors, EDLCs) or via faradaic reactions from redox‐active species dissolved in the media or coated on the electrodes (so‐called pseudocapacitors, PCs) . In general, the capacitance of a PC is much higher in comparison to an EDLC . Compared with batteries, SCs feature the advantages of fast charging/discharging rates, long cyclic life, and high power densities .…”

“…To fabricate high‐performance SCs, the first key issue is to achieve big and stable capacitances. It is known that the capacitance of an SC is directly related to the obtained surface area as well as to the conductivity and stability of the used capacitor electrode . Carbon materials have been extensively employed for the construction of SCs since they fit well these requirements.…”

“…The used electrolyte is the second key factor that one needs to take into serious consideration when high‐performance SCs are planned to be constructed . Taking the fabrication of EDLCs as an example, the conductivity of aqueous solutions is generally higher than that of organic solutions, whereas the working potential range of aqueous solutions (due to water electrolysis) is narrower than that of organic solutions.…”

“…However, for the construction of high‐performance SCs, they suffer from high viscosity, limited scales for their production, and low efficiencies of their recycling. On the other hand, the introduction of redox‐active species onto the capacitor electrodes or into the solutions is proved recently to be a promising approach to develop high‐performance PCs . Their energy densities are even comparable with those of batteries .…”

“…On the other hand, the introduction of redox‐active species onto the capacitor electrodes or into the solutions is proved recently to be a promising approach to develop high‐performance PCs . Their energy densities are even comparable with those of batteries . Surprisingly, the construction of SCs in both aqueous and organic solutions using the same capacitor electrode under identified conditions (e.g., same working voltages) is seldom reported.…”