Nanocarbon from Rice Straw as Supercapacitor Electrode

Rice straw waste in Indonesia is abundant and not yet used optimally. The composition of rice straw is 40% cellulose, 30% hemicellulose, 15% silica and 15% lignin so it is potentially to be a raw material of active carbon and supercapasitor electrode. Many efforts has been done to increase the value of capacitance of electrode like increase the surface area with activation and milling process. In this research used the variation of activator substance and the variation of milling velocity, they are H3PO4 450 rpm, H3PO4 600 rpm, and KOH 450 rpm. The purposes of this research are identify and characterize the rice straw charcoal material as nanocarbon and also knowing the nanocarbon quality of rice straw charcoal material as supercapacitor electrode. The methods are carbonization, activation, and solid state reaction. The result of this research shows the value of capacitance at H3PO4 450 rpm, H3PO4 600 rpm, and KOH 450 rpm are 28,96 F/g; 30,89 F/g; dan 19,31 F/g. From this research, we can conclude that activator substance and milling velocity affect the value of capacitance that is produced. The result of SEM-EDX test is comparable with the result of cyclic voltammetry test, the higher number of pores the higher value of capacitances produced.

An Electroactive Polymer Modified Separator with A Potential Clamp Function

An inexpensive electroactive polymer polytriphenylamine (PTPAn) was synthesized through chemical oxidative polymerization of TPA. The composite separator was simply prepared by impregnating a commercial PP separator with PTPAn polymer solution. PTPAn was observed on the surface of the composite separator and formed a uniform coating. In cyclic voltammetry test, PTPAn polymer exhibited a pair of well-defined redox peaks between 3.0 and 4.5 V, which could be regarded as a reversible electrochemical p-doping and dedoping process. When incorporated in a blocking cell, the composite separator was able to hold a constant potential for current densities up to 5 mA/cm2 to protect the cell from overcharging.

Fabrication of Ultra-Low Density, High Surface Area Carbon Aerogels and their Application in Supercapacitors

The ultra-low density carbon aerogel, as low as 20 mg/cm3, was fabricated by pyrolysis of the organic aerogel formed by aqueous condensation of resorcinol and formaldehyde. Its surface area was as high as 1783 m2/g and it was used for investigation of electrochemical capacitive behaviours. The ultra-low density carbon aerogel displayed capacitive performance (110 F/g at 0.2 A/g) in 6 M KOH aqueous solution. Additionally, over 98% of the initial capacitance was retained after repeating the cyclic voltammetry test for 1000 cycles. The electrochemical performance might be attributed to the combination of three dimensional “opened” structure and high surface area of the carbon aerogel.

Lithium-Ion Battery Anode Based on Thinning Si Microchannel Plate Coated with Copper Current Collector

In this paper, chemical etched Si microchannel plates (Si-MCPs) is fabricated to use as lithium-ion battery anode. Copper formed by chemical deposition was served as current collector. The chemical etched Si-MCP with copper current collector exhibited a better cycle performance in the galvanostatic charge-discharge measurements. The reaction mechanism was also investigated based on cyclic voltammetry test.

Acidification Assisted Preparation of Graphite Oxide and Graphene

Graphite oxide was prepared by acidification assisted Hummers method, which contains acidification, medium temperature and high-temperature three stages. Traditional Hummers low-temperature process was replaced by acidification process. The dosages of acid, graphite and potassium permanganate were investigated, and the produced graphite oxide was treated by ultrasonic oscillation and reduced to graphene by refluxing the reaction mixture at 100°C under open-air conditions. The structure of natural graphite, graphite oxide and graphene were characterized by X-ray diffractometry and infrared spectrum, the morphology of graphene was observed on a scanning electron microscope and the electrochemical properties of graphene were analyzed by the three-electrode cyclic voltammetry test system.

Synthesis of Nickel Nanoparticles/Multiwalled Carbon Nanotubes Composites with Pre-Treated Multiwalled Carbon Nanotubes as Modifier

A simple synthetic route to create Nickel nanoparticles/MWCNT composites (NiNPs/MWNTs) is reported. The process is concise, no additional surfactant or other reducing gas was employed. TEM, SEM, XRD and EDX were used to examine the morphology of the nickel particles. In this experiment, the hydrothermal method using ethylene glycol as a solvent has been well dispersed, uniform size and smaller particle size of the nickel nanoparticles with average size about 50 nm. By cyclic voltammetry test results show that with good electrical properties, Ni / MCNTs.

Pulse cyclic voltammetry. I. Static solutions

By using pulse cyclic voltammetry rather than cyclic voltammetry at a relatively high scan rate, an increase in sensitivity and a lowering of the detection limit by more than a factor of two are demonstrated for the ferricyanide–ferrocyanide couple at a carbon electrode. The test for reversibility based on peak shape or symmetry comparison is enhanced significantly with pulse cyclic voltammetry. Another reversibility test, by observing peak variations as a function of scan rate, was applied to pulse cyclic voltammetry and was found to be as diagnostically informative as the cyclic voltammetry test. These tests are illustrated by a study of the hydroquinone–quinone couple.