High Potential of Aerosol‐Made 3D Graphene‐Based Composites for Enhanced Energy Storage

Abstract

another very important type of advanced energy storage system, and they are highly useful and promising devices for related storage purposes. [6] Batteries that maintain high energy density levels, high operability, and long cycling lifetimes are regarded as the most promising power source for portable devices and electric vehicles. [7] Typical batteries consist of an anode, a cathode, an electrolyte, and a separator. [8] The performance of these electrochemical energy conversion or storage systems is highly dependent on the properties of the active electrode material. Graphene (GR), a flat single layer of sp 2 -bonded single carbon atoms, has recently attracted strong interest as the most promising active electrode material due to its high specific surface area, high thermal conductivity, excellent mechanical rigidity, fast electronic transport, high optical transparency, and other useful properties. [9,10] However, conventionally prepared GRs by the liquid-phase reaction are formed mostly as 2D layered GR sheets and tend randomly or easily to aggregate, repackage, and restack by means of π-π stacking and van der Waals attraction. [11,12] The random stacking of GR sheets reduces the specific surface area and thus decreases the electrochemical performance. [11,12] To overcome these drawbacks of random stacking of GR, many researchers have studied 3D GR for energy storage systems by various liquid-phase, freeze-drying methods, and so on. In previous studies, Qu et al. introduced GR-polyaniline (PANI) composites by hydrothermal for high-rate performance in supercapacitors. [13] Xu et al. produced 3D porous GR and metal-organic framework composites by freeze-drying, which showed a good rate capability with high specific capacitances. [14] Zhang et al. also showed metal-organic framework/GR composite fibers by wet-spinning and as-prepared composites indicated high electrochemical performance. [15] However, the above methods are time-consuming and disadvantageous in that the control of shape is difficult. The fabrication of 3D GR by an aerosol process is considered as a highly promising type of platform technology with many advantages to solve problems of previous methods. The aerosol process is advantageous to fabricate various composites in less than a few minutes with certain compositions of colloidal precursor solutions that contain GO and any type of dissolved metal-based compound. [16][17][18] Figure 1 shows a schematic illustration of various 3D GR-based composites formed from a graphene oxide (GO) and component colloidal mixture by an aerosol process. Various aerosol-made 3D Graphene CompositesRecently, many researchers have developed advanced energy storage and energy conversion systems to address the increased demand for energy resources. The performance of these electrochemical energy storage and conversion devices depends considerably on the properties of their unique electrode materials. Among electrode materials, graphene (GR) has attracted much attention due to its unique properties of high flexibility,...

Facile one-pot synthesis of NiCo2Se4-rGO on Ni foam for high performance hybrid supercapacitors

“…3(a) the near rectangular CV curve of rGO on Ni foam in the potential range of 0-0.6 V vs. Ag|AgCl is typical of EDLC charge storage mechanism, as could be expected from porous conducting carbonaceous matrix. [15][16][17] With NiCo 2 Se 4 on the other hand, the distinctive redox peak in the potential range of 0-0.5 V vs. Ag|AgCl veried the electrochemical pseudocapacitor-like behavior of this compound. The CV curve of NiCo 2 Se 4 -rGO@NF as shown in Fig.…”

“…5 The supercapacitors can be classied into three categories based on their charge storage mechanism and use of active electrode materials: (i) electrochemical double layer capacitor (EDLC) which stores charge in highly porous or high surface area electrodes such as carbon-based materials including graphene, CNTs etc. ; [15][16][17] (ii) pseudocapacitors, also known as redox supercapacitors, which stores charge through reversible electrochemical redox reactions using the variable oxidation states of transition metal based centers in the corresponding oxides, [18][19][20][21] hydroxides, [21][22][23][24] chalcogenides [25][26][27][28] as electrode materials; (iii) hybrid electrochemical capacitor which are a combination of both EDLCs and pseudocapacitors and incorporate redox-active transition metal-based centers onto high surface area, porous electrodes. [29][30][31][32] EDLCs store charge electrostatically via generation of electrical double layer in the non-faradaic region at the interface between electrode and electrolyte.…”

Physical Origin of Distinct Mechanical Properties of Polymer Tethered Graphene Nanosheets Reinforced Polymer Nanocomposites Revealed by Nonequilibrium Molecular Dynamics Simulations

“…As "the most marvelous material in 21st century", growing research attention has been paid to graphene as well as its derivatives, which is one-atom-thick 2D layer of sp 2 -bonded carbon nanosheet materials, arranged in a honeycomb structure. [15,16] Due to the excellent mechanical, electrically and thermally conductive properties as well as lightweight, there has been an explosion of emphasis on the graphene nanosheets (GN) reinforced PNCs, which show many potential applications in the field of sensors, [17] flexible and wearable devices, [18,19] electrodes, [20,21] electromagnetic interference shielding, [22,23] and other high-performance functional composite materials. [24][25][26][27] However, the self-aggregation of GNs seriously do harm to or even destroy the properties of the final PNCs.…”