Spinel NiCo2O4 based hybrid materials for supercapacitors: Recent developments and future perspectives

We report a simple and low-cost technique to prepare a composite comprising of activated carbon and few layers of graphene sheets and fabricated as electrode material for supercapacitor (SC) applications. The composite is characterised by using Raman spectroscopy, powder X-ray diffraction (XRD), scanning electron microscope (SEM) and current-voltage (I-V) measurements. The synthesized composite is investigated by using galvanostatic chargedischarge (GCD) and cyclic voltammetry (CV) measurements in 3M KOH aqueous electrolyte to evaluate its electrochemical performance. The composite results high specific capacitance from 173 to 564 F/g at different scan rates (100-5 mV/s), analysed by CV and the capacitances resulted in GCD measurement were 196 to 587 F/g at various current densities (5-1 A/g). The cycle stability of the as-prepared AC/graphene composite is also tested and observed that 89% of capacitance is retained even after 5000 cycles which reveals the excellent long term chargedischarge stability of the prepared composite. Therefore, the composite performs very well in storage as well as life cycling. The obtained results suggest that AC/graphene composite can be a suitable electrode material for high-performance SC.

Carbon quantum dots anchoring MnO2/graphene aerogel exhibits excellent performance as electrode materials for supercapacitor

Recently, metal oxynitrides (MONs) have gained a lot of attention as electrode materials for supercapacitor (SC) applications due to their unique properties such as high electronic conductivity, wettability, corrosion resistance, and chemical robustness. Nanostructuring strategies of MONs opens fresh avenues for energy storage. Though various transition metal oxides (MO) and metal nitrides (MN) have been explored as electrode materials for SC applications, they have limitations associated with poor cyclability and rate capabilities. Hence, there is a value to exploring intermediate oxynitride compounds (MONs) in place of pure MOs and MNs. Chromium oxynitride (CrOXNY) as electrode material is not yet been explored for SC applications. In this context, we have carried out the systematic study of the nanostructured nano‐spherical CrOXNY nanoparticle as an electrode material for SC applications. The electrochemical performance of the CrOXNY electrode is tested in both the three and two electrode assembly. The CrOXNY electrode shows capacitance of 146 F g−1 at 10 mV s−1 in three electrode configuration. The symmetric coin cell (CR2032) is fabricated and tested up to 10,000 cycles at 2 A g−1 and it shows excellent capacity retention up to 98 %. The energy and power densities of the symmetric device are ∼8 W h kg−1 at 1 A g−1 and 28.8 kW kg−1 at 10 A g−1, respectively. As a proof of concept, a red light‐emitting diode (LED) is lit by serially connecting two symmetric coin cells (2 V). These attributes of CrOXNY, such as excellent capacitance retention, long cyclic stability, and high rate capability, indicates that it can be used as a durable electrode material for SC technology.

Metal-organic framework-derived porous MnNi2O4 microflower as an advanced electrode material for high-performance supercapacitors

Supercapacitors, a new energy storage element based on electrochemical double layer capacitance, store energy by ion adsorption, have recently attracted increasing interest with the sharp development of nanostructure materials. Supercapacitors store and release energy by nanoscopic charge separation at the interface between an electrode and an electrolyte, and the energy restored in it is inversely proportional to the thickness of the double layer. Due to its high power density, long cycle life, low weight, flexible packaging and a wide thermal operating range compared to other conventional energy storage devices, supercapacitor can be used as a potential energy device bridging the gap between chemical power and common electrostatic capacitance. However, a distinct defect for supercapacitor is the energy density lower than rechargeable batteries. Electrode material is the key to improve the performance of supercapacitor, so most of researches current is around searching electrode materials with higher specific capacitance. Fortunately, graphene as a single atomic of graphite was found to be suitable for electrode materials in supercapacitors owing to its super conductivity and high specific area. In this paper, we report a study on graphene as the electrode material in supercapacitor.

Supercapacitor is a promising energy storage device, which has many advantages including long service lifetime, great power density, fast charge-discharge processes, and green environmental protection. The properties and performance of supercapacitors are greatly dependent on the electrode materials; hence the selection of the electrode material is crucial. There are many metal oxides which have been reported for supercapacitors and ultracapacitors; however, its performance is not that as expected. Thus high-performance electrode materials with large surface area and specific capacitance have been a topic of interest for the development of high-performance supercapacitors. Recently, two-dimensional (2D) transition metal dichalcogenides having layered structures, such as MoS2, VS2, SnS2, CoS2, and WS2, have received significant attention because they offer good energy density, power density, and cycling stability. Among them, the layered molybdenum disulfide (MoS2) is considered to have great potential for its applications as supercapacitors. MoS2 nanosheet is composed of one Mo atomic layer sandwiched between two S layers by covalent bonding, and with these triple layers stacked together to form a layered structure, is expected to act as an excellent energy storage material. It is because of the 2D electron–electron correlations among Mo atoms which would aid in enhancing planar electric transportation properties. MoS2 nanosheets can deliver excellent pseudocapacitance because of the Mo ions having oxidation states ranging from +2 to +6, which enable them to be used as high-performance electrode materials in supercapacitors. Indeed, as a graphene analogue, MoS2 nanosheets exhibit unique physical, optical, and electrical properties correlated with its 2D ultra-thin atomic layer structure and high surface area, making it very interesting for its use as electrodes in high-performance supercapacitors and also a promising supporting material to stabilize metal nanoparticles (NPs), forming hierarchical composites. The specific capacitance of MoS2 is still very limited in alone for energy storage applications. The combination of MoS2 and other conducting materials such as graphene, carbon nanotubes (CNTs), or ceramic nanomaterials such a zirconium (Zr) may overcome these deficiencies. This chapter gives a clear picture of the applications of MoS2 as high-performance electrode in supercapacitors.

Spray drying-assisted preparation FeSx/C/CNT composite for energy storage and conversion performance

ZIF-67 derived nitrogen doped CNTs decorated with sulfur and Ni(OH)2 as potential electrode material for high-performance supercapacitors

Blue TiO2 nanosheets as a high-performance electrode material for supercapacitors

7 - Design and synthesis of ultrathin graphene: Fundamental applications in transparent electrodes and supercapacitors

Sonochemical synthesis of welded titanium dioxide-silver nanocomposite as a 3-dimensional direct ink writing printed cathode electrode material for high-performance supercapacitor

Design and construction of core-shell heterostructure of Ni-V layered double hydroxide composite electrode materials for high-performance hybrid supercapacitor and L-Tryptophan sensor

Molybdenum and sulfur co-doped CoNiO2 with tremella-like nano-structures as electrode material for high-performance supercapacitors

Homogeneous nickel bicarbonate nanocrystals as electrode materials for high-performance asymmetric supercapacitors

Fe3O4@PPy@MnO2 ternary core-shell nanospheres as electrodes for enhanced energy storage performance