Spinel LiMn2O4 Nanorods via Template–Engaged Method and as Cathode Materials for Li-Ion Batteries

Spinel LiMn2O4 nanorods were prepared by a hydrothermal method followed by solid-state lithiation. The produce β-MnO2 nanowire as template, and LiOH·H2O was used as lithium source. The spinel LiMn2O4 nanorods samples were characterized by SEM, XRD, (HR)TEM, and galvanostatic charge/discharge profile measurement. Compared with the LiMn2O4 nanoparticles, the LiMn2O4 nanorods showed superior cycling stability, better rate capability, good high temperature performance, and delivered a discharge capacity of 122 mAh/g (at 1 C, 100 cycles).

Use of a zeolite slurry to increase the charge retention of a low-cost aqueous supercapacitor

<p>To increase the viability of renewable energy technology, improvements must be made to existing energy storage devices. One such device is the supercapacitor, which is able to store energy like a battery, but with faster charge-discharge times and increased cyclability. The two main factors limiting the widespread use of supercapacitor technology are the high component cost and high rate of self-discharge. In this project, both of these aspects were addressed, and a supercapacitor was successfully constructed using a carbon black slurry containing zeolitic structures with a pore size of 4 Å to accommodate the electrolyte ions of potassium and chloride. Low-cost materials and production methods were used to create a supercapacitor with a measured capacitance of 17.25 F g⁻¹ and a coulombic efficiency of 100% determined by galvanostatic charge-discharge curve measurements.</p>

Use of a zeolite slurry to increase the charge retention of a low-cost aqueous supercapacitor

<p>To increase the viability of renewable energy technology, improvements must be made to existing energy storage devices. One such device is the supercapacitor, which is able to store energy like a battery, but with faster charge-discharge times and increased cyclability. The two main factors limiting the widespread use of supercapacitor technology are the high component cost and high rate of self-discharge. In this project, both of these aspects were addressed, and a supercapacitor was successfully constructed using a carbon black slurry containing zeolitic structures with a pore size of 4 Å to accommodate the electrolyte ions of potassium and chloride. Low-cost materials and production methods were used to create a supercapacitor with a measured capacitance of 17.25 F g⁻¹ and a coulombic efficiency of 100% determined by galvanostatic charge-discharge curve measurements.</p>

Magnetic and electrochemical properties of nickel oxide microstructures prepared by hydrothermal method

Nickel oxide microstructures were succesfully synthesized by hydrothermal method. The structure, morphology, surface and porosity of the NiO hexagonal plates indicated the formation of NiO without appearing any secondary phases, occupying the typical cubic structure. The ferromagnetic behaviour was examined by vibrating sample magnetometer (VSM). The sample exhibited ferromagnetic behaviour at room-temperature with the magnetic moment value of ~ 160 memu/g. The cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) anylysis were used to examine the electrochemical capacitance of the sample. The specific capacitance of the sample at a current density of 1 A/g was obtained to be 174.14 F/g. The cycle stability was excellent usability 76.6% after 500 cycles at a current density of 5 A/g.

The Electrochemical Performance of δ-MnO2 Cathode Material for Aqueous Zinc-Ion Batteries: The Role of Current Collector

Electrochemical properties of δ-MnO2-based cathode materials were studied in dependence on current collector used for electrode casting (stainless steel mesh, carbon paper and titanium foil) by galvanostatic charge/discharge measurements and cyclic voltammetry. It was shown that δ-MnO2-based electrodes cast on carbon paper demonstrate the most stable electrochemical performance in comparison with two other current collectors. This can be explained by corrosion of steel and passivation of titanium in mild aqueous electrolytes. Detailed study of carbon paper as current collector shows that pressing of electrodes leads to decreasing the porosity and fast capacity fading.

Modeling galvanostatic charge–discharge of nanoporous supercapacitors

Molecular modeling has been considered indispensable in studying the energy storage of supercapacitors at the atomistic level. The constant potential method (CPM) allows the electric potential to be kept uniform in the electrode, which is essential for a realistic description of the charge repartition and dynamics process in supercapacitors. However, previous CPM studies have been limited to the potentiostatic mode. Although widely adopted in experiments, the galvanostatic mode has rarely been investigated in CPM simulations because of a lack of effective methods. Here we develop a modeling approach to simulating the galvanostatic charge–discharge process of supercapacitors under constant potential. We show that, for nanoporous electrodes, this modeling approach can capture experimentally consistent dynamics in supercapacitors. It can also delineate, at the molecular scale, the hysteresis in ion adsorption–desorption dynamics during charging and discharging. This approach thus enables the further accurate modeling of the physics and electrochemistry in supercapacitor dynamics.

STUDY OF STRUCTURAL AND ELECTROCHEMICAL PROPERTIES OF 3-D MICROFLOWER-LIKE NICKEL HYDROXIDE

Recent work reported on nickel hydroxide chemically synthesized by simple cast effective chemical bath deposition method at room temperature. During reaction, nanoflakes developed and time enhance nanoflakes interlinked to form marigold like microflower which reveals from SEM. Structural properties analysis by XRD and FT-IR gives hexagonal crystal structure and presence of Ni-O bond to confirmation of deposition of Ni(OH) material. Highest value of specific 2 -1 capacitance of electrode at deposition time 90 min without aniline from Cyclic voltammetry is 553 Fg at scan rate 10 mV -1 -1 -2 -1 -1 s and from Galvanostatic charge discharge 215 Fg at current density 3 mA cm with 6.04 W h kg and 1687.5 W kg of energy and power density respectively. EIS analysis reveals least charge transfer resistance of 90min deposition time electrode.

Analysis of Cyclic Voltammetry dan Galvanostatic Charge Discharge Electrode Supercapacitor based on activated carbon from Kepok Banana Leaf (Musa balbisiana)

Abstrak. Teknologi penyimpan energi elektrokimia yang ramah lingkungan merupakan aspek yang penting dalam menunjang kinerja sistem konversi energi terbarukan. Studi ini menyiapkan elektroda superkapasitor berbahan asal karbon aktif berpori limbah daun pisang kepok. Sampel dipreparasi melalui impregnasi Natrium hidroksida pada konsentrasi 0,5 m/L dan dipirolisis satu tahap meliputi karbonisasi dan aktivasi fisika. Serbuk karbon yang dihasilkan dikonversi dalam bentuk pellet atau monolit dengan menggunakan hidraulik press tanpa adanya penambahan bahan perekat. Proses karbonisasi dilakukan dari suhu kamar hingga 600 °C pada lingkungan gas N2 sedangkan proses aktivasi fisika dilakukan dari suhu 600 °C hingga pada suhu tinggi dengan tiga jenis suhu yang berbeda meliputi 700 °C, 800 °C, dan 900 °C pada lingkungan gas CO2. Analisis densitas ditinjau sebagai evaluasi awal elektroda karbon berpori. Lebih lanjut, sifat elektrokimia superkapasitor dievaluasi melalui dua teknik yang berbeda meliputi teknik cyclic voltammetry (CV) dan galanostatic charge discharge (GCD) pada sistem dua elektroda dalam elektrolit 1 M H2SO4. Kapasitansi spesifik pada teknik CV adalah sebesar 142 F/g sedangkan dengan teknik GCD menghasilkan kapsitansi spesifik sebesar 154 F/g pada resistansi 42∙10-3Ω. Rapat daya dan rapat energi yang dihasilkan berturut-turut 20,45 Wh/kg dan 38,32 W/kg. Hasil ini mengkonfirmasi bahwa daun pisang berpotensi dijadikan sebagai karbon aktif berpori untuk material dasar elektroda superkapasitor.Abstract. Environmentally friendly electrochemical energy storage technology is an important aspect of supporting global energy fulfillment as a contribution to improving the performance of renewable energy conversion systems. Currently, supercapacitors are considered as a superior electrochemical energy storage technology compared to others. This study performed a supercapacitor with electrodes made from porous activated carbon based on biomass waste, especially banana leaf waste. The sample was prepared by sodium hydroxide impregnated at a concentration of 0.5 m/L dan one-step pyrolysis both carbonization dan physical activation. The carbon powder is converted into pellets or monoliths using a hydraulic press without the addition of any adhesive materials. The carbonization process is performed from room temperature to 600 °C in an N2 gas environment while the physical activation process is carried out from a temperature of 600 °C to a high temperature with three different types including 700 °C, 800 °C, dan 800 °C in CO2 gas atmosphere. Density analysis is reviewed as an initial evaluation of the porous carbon electrode. Furthermore, the electrochemical properties of the supercapacitor were evaluated through two different techniques including cyclic voltammetry (CV) dan galvanostatic charge-discharge (GCD) in a two-electrode system in 1 M H2SO4 electrolyte. The specific capacitance in the CV technique is 142 F/g while the GCD technique produces a specific capacitance of 154 F/g at resistance of 42∙10-3 Ω. The power density dan energy densities for the K-900 are 20.45 Wh/kg dan 38.32 W/kg, respectively. These results confirmed that banana leaves have the potential to be used as porous activated carbon for the supercapacitor electrode.

Etlingera elatior leaf agricultural waste as activated carbon monolith for supercapacitor electrodes

Recently, biomass waste has become the focus of several researchers because it has promising potential when processed into porous activated carbon. Abundant availability, uncomplicated processing, and more economical are the reasons for choosing biomass as the basic material for making carbon electrodes for electric energy storage supercapacitors. In this study, Etlingera elatior waste biomass is processed into activated carbon by heating at high temperature and impregnation of 0.5 M ZnCl2. The monolith sample was optimized through a single-stage integrated high-temperature pyrolysis process. Where the process of carbonization of N2 gas from a temperature of 30 °C to 600 °C followed by a physical activation process of CO2 gas to a temperature of 800 °C. Determination of the physical properties of the electrodes through density characterization, while the electrochemical properties were analyzed by cyclic voltammetry and galvanostatic charge discharge methods. Cyclic voltammetry and galvanostatic charge discharge analysis were performed with 1 M Na2SO4 aqueous electrolyte at a voltage of 0–1 V and a scan rate of 1 mV/s. Furthermore, the high electrochemical behavior of the CV method was found to be 108 F/g, while for the gcd method, the specific capacitance was much higher at 148 F/g at a constant current density of 1.0 A/g. Further calculations found an energy density of 8.23 Wh/kg and a power density of 161 W/kg. These results support the optimization of 0.5 M ZnCl2 impregnated Etlingera elatior leaves as the base material for activated carbon electrodes to increase the supercapacitor capacitance.

Composite C/MnO2 electrodes for electrochemical capacitors based on water electrolyte

The electrochemical properties of C/MnO2 composite materials in 1 M sodium sulfate solution were investigated using the methods of cyclic voltammetry, galvanostatic charge-discharge and impedance spectroscopy. It was shown that the capacitive characteristics of the electrodes depend on the nature and the method of obtaining manganese oxide nanoparticles. It was established that the material containing manganese oxide obtained using isoamyl alcohol as a reducing agent has high electrochemical characteristics.