Electrochemical and electrical properties of nickel molybdate / carbon material composites

The aim of this paper is to establish the optimal content of carbon material in composites with nanocrystal hydrate nickel molybdate. To achieve this, NiMoO4 / C composites with a carbon material content of 1, 5 and 10% by weight (with and without ultrasonic irradiation) were obtained by hydrothermal method. As a result of electrochemical studies, it was found that the maximum specific capacitance of 628 F/g is reached by a composite with a carbon content of 1% after ultrasonic exposure, while this composite shows excellent electrical conductivity, which is 0.47 Ohm-1m-1.

Assessing Strong Consistency of Symmetrical Solid-state Supercapacitors Based on Three-dimensional Porous Carbon Material

Three-dimensional (3D) porous carbon material enhances the electrochemical performance of symmetrical solid-state supercapacitors which are prepared by using abundant biomass waste as electrodes and (PVA-Li2SO4) gel polymer electrolyte. A saving and simple carbonization method with KOH chemical activation is developed for synthesizing highly porous carbon from peanut shell with high specific surface area of 1348 m2 g–1, which can be reused the chemical activation solution. The electrodes making by such three-dimensional porous carbon in a 1 M Li2SO4 electrolyte demonstrates a maximum specific capacitance of 386 F g–1 at current density of 2 A g–1, energy density and power density of 53.61 Wh k g–1 and 1000 W kg–1, respectively. The symmetrical solid state supercapacitors with sandwich structure of (3D porous carbon P/PVA-Li2SO4/3D porous carbon P) exhibits a maximum specific capacitance of 116 F g-1 at current density of 0.5 A g–1. The energy density and power density are the value of 9 W h kg–1 and 380 W kg–1, respectively. Further, the supercapacitors also demonstrate good cycling stability 89 % retention after 7000 cycles.

Facile Preparation of Commercial Bi2O3 Nanoparticle Decorated Activated Carbon for Pseudocapacitive Supercapacitor Applications

In this work, a facile method to prepare commercial nano-Bi2O3/carbon composites with high pseudocapacitive properties was presented. The inorganic-organic composites synthesized by using commercial bismuth oxide and active carbon with different weight ratio. The composites were characterized using microscopic, spectroscopic, and diffractive methods. Our assessments confirmed that active carbons were successfully doped with commercial Bi2O3 nanoparticles with different dopant rates. The composites exhibited a maximum specific capacitance of 517 F/g at a current density of 1 A/g for 20% Bi2O3 nanoparticle doped activated carbon samples. Augmented discharging time was also achieved for increased Bi2O3 nanoparticle doping rate. Increased Bi2O3 dopant rate also increased the calculated specific capacitance.

Integration of 3D interconnected sodium hydroxide modified biochar with the tile-like architecture of cobalt oxides for asymmetric supercapacitors

Two state-of-the-art electrodes were successfully synthesized and used to assemble both symmetric and asymmetric type supercapacitors. 3DFAB was fabricated by direct pyrolysis of green macroalgae in the presence of NaOH. Possible mechanisms of NaOH activation is proposed, which explains the formation of oxygen functional groups through quick penetration of OH- and NaOH into the vacancies. To obtain CoTLM, the tile-like architecture of cobalt oxides was introduced to the 3D interconnected functional algal biochar (3DFAB) by a simple one-pot hydrothermal method under mild conditions. For the symmetric supercapacitors, the maximum specific capacitance of RAB, 3DFAB, and CoTLM were 177 F g− 1, 322 F g− 1, and 529 F g− 1 at a scan rate of 5mVs− 1. Regarding cobalt-based asymmetric systems, the maximum capacitance for the RAB//CoTLM and 3DFAB//CoTLM were ∼300 F g− 1 and 400 F g− 1, respectively. The 3DFAB//CoTLM showed a higher energy density compared with RAB//CoTLM, while the RAB//CoTLM exhibited better cycling performance (99.1% of its initial capacitance after 4 k cycles at the current density of 4 A g 1).

Development and Characterization of SDS Doped Poly(aniline-co-2-isopropylaniline) MWCNT/CuO Nanocomposites for Electrochemical Supercapacitor Application

A novel electroactive nanocomposite material containing aniline-co-2-isopropylaniline (Pani-co), SDS doped poly-Pani-co, copper oxide (CuO), and multiwalled carbon nanotubes (MWCNTs) has been developed by in situ oxidative synthesis technique. The electrochemical execution of synthesised composite as electroactive supercapacitor material was examined through three electrode cell assembly viz. cyclic voltammetry (CV), galvanostatic charge/discharge analysis (GCD) and electrochemical impedance study. Physical and chemical characteristics of synthesized SDS doped Pani-co/MWCNT/ CuO nanocomposite were explored via FTIR, TGA, XRD, FESEM and EDX methods. The results confirmed that the existence of metal oxide on MWCNTs enhanced the redox activity of the prepared composite. The maximum specific capacitance obtained in cyclic voltammetric studies was 1473 F/g at sweep rate of 3mV/s, and the maximum specific capacitance obtained with GCD studies was 1512 F/g at current density of 1A/g in 1M Na2SO4 aqueous solution of with better cycle life.

Effect of Redox Additive Electrolyte on the Electrochemical Performance of MnO2 Nanorods for Supercapacitor Application

Pure MnO2 nanorods were synthesized by hydrothermal method and characterized by different techniques to analyze their crystalline nature, surface morphology, functional groups, and optical properties. XRD analysis confirms that the prepared nanorods possess a tetragonal crystalline structure. The occurrence of nanorods was confirmed by SEM analysis and its elemental composition was studied by elemental mapping. MnO2 nanorods modified working electrode was fabricated by the deposition of prepared nanorods on nickel foil. Electrochemical performance of the MnO2 nanorods modified working electrode was studied using redox additive based electrolyte containing 0.1M K4 [Fe(CN)6 ] in 1M KOH solution. The maximum specific capacitance of the prepared nanorods in 1M KOH electrolyte was 89 Fg-1 and it is greatly enhanced by the addition of 0.1M K4 [Fe(CN)6 ] redox additives (634 Fg-1 ).

Synthesis and Electrochemical Examination of Fe2O3/CeO2 Nanocomposite for Supercapacitor Application

Fe2O3 /CeO2 nanocomposite was synthesized by a chemical precipitation method in room temperature. The prepared nanocomposite has been subjected to some characterization techniques such as XRD, SEM, FTIR, CV, etc., The presence of crystalline phases of CeO2 and Fe2O3 were confirmed by the powder X–Ray diffraction analysis. Surface morphology of the prepared nanocomposite has been analyzed using SEM analysis. The functional group vibrations were analyzed by FTIR technique. The maximum specific capacitance achieved by using 1M KOH electrolyte solution is about 242 Fg-1 at 5 Ag-1 current density.

Controllable Zn0.76Co0.24S Nanoflower Arrays Grown on Carbon Fiber Papers for High-Performance Supercapacitors

A nanoflower structure of Zn[Formula: see text]Co[Formula: see text]S directly grown on carbon fiber papers (CFP) was successfully designed by a mild two-step hydrothermal method. Benefiting from their fascinating structural features, Zn[Formula: see text]Co[Formula: see text]S/CFP electrode exhibits a maximum specific capacitance of 300[Formula: see text]F[Formula: see text]g[Formula: see text] at current density of 1[Formula: see text]A[Formula: see text]g[Formula: see text] and 84% capacitance retention after 5,000 cycles at current density of 5[Formula: see text]A[Formula: see text]g[Formula: see text]. Subsequently, Zn[Formula: see text]Co[Formula: see text]S/CFP//AC all-solid-state asymmetric supercapacitor (ASC) device is assembled and able to illuminate the red LEDs. ASC devices deliver a maximum energy density of 9.59[Formula: see text]W[Formula: see text]h[Formula: see text]kg[Formula: see text] at a power density of 750[Formula: see text]W[Formula: see text]kg[Formula: see text]. Therefore, this impressive result demonstrates that the nanoflower Zn[Formula: see text]Co[Formula: see text]S have promising applications in the development of high-performance supercapacitors.

Multifunctional structural supercapacitor based on graphene and magnesium phosphate cement

A novel structural supercapacitor is assembled with graphene electrodes and the magnesium phosphate cement separator. Magnesium phosphate cement acts as separator material for the first time due to its high strength and relatively high porosity. Magnesium phosphate cement is synthesized by acid-based reaction between phosphate and magnesia. Effects of processing parameters of magnesium phosphate cement, including M/P ratio and the curing time, on the electrochemical and mechanical properties are investigated. The maximum specific capacitance is as high as 46.38 F g−1 with M/P ratio of 3 at the curing time of 1 day. Moreover, the structural supercapacitor exhibits a specific capacitance of 40.92 F g−1 and simultaneously a compressive strength of 24.59 MPa with the M/P ratio of 3 at the curing time of 28 days. Thus, the optimal M/P ratio is 3 regarding the multifunctionality of structural supercapacitor.

Novel corn cob-like Fe3O4@Ni3S2 as high-performance electrode for supercapacitors

Corn cob-like Fe3O4@Ni3S2 nanocomposites was synthesized through a facile two-step hydrothermal process. The precursor was obtained by a facile calcination of a Fe-MOF template, then, nickel sulfide coated on iron oxide composites were synthesized using a hydrothermal method. In addition, the fabricated Fe3O4@Ni3S2 electrode revealed a great electrical performances with a maximum specific capacitance of 1200[Formula: see text]F[Formula: see text]g[Formula: see text] at 1[Formula: see text]A[Formula: see text]g[Formula: see text], a capacitance retention of 83% could be observed after 1000 cycles at a great charge–discharge current density of 5[Formula: see text]A[Formula: see text]g[Formula: see text]. We believed that the excellent performance might be ascribed to the synergistic effect between the Fe3O4and Ni3S2. Thus, the results demonstrate the corn cob-like Fe3O4@Ni3S2 composite is prominent candidate in the field of supercapacitor applications.