Charge storage in the PANI-α-MnO2polymer-nanocomposite system

Supercapacitors (SCs) store electrochemical energy with high specific power, faster charge response, and long cycle life at an electrode-electrolyte interface; however, with lower specific energy than commercial batteries. In this article, structural, morphological, surface and electrochemical properties of a polymer-nanocomposite in the PANI-α-MnO2 system has been systematically investigated. The α-MnO2was synthesized by molten salt methods and the polymeric composite was developed by in-situ polymerization. The materials were characterized by thermal analyses, X-ray and electron diffraction, FTIR spectroscopy, gas adsorption studies, scanning and transmission electron microscopy. The electrochemical properties of the materials before and after PANI modification are studied in 6 M KOH aqueous electrolyte employing cyclic voltammetry, galvanostatic charge-discharge cycling, and electrochemical impedance spectroscopy. A difference in charge storage mechanism from pseudocapacitive type to battery-type was observed upon PANI modification and the corresponding charge storage and charge kinetic parameters have been detailed

Thin chemisorbed polyaniline film on cobalt oxide as an electrode for hybrid energy storage devices

Electrical charge storing electrodes and their surface modification are intensively investigated to improve the charge storability indicators in electrochemical energy storage devices. Here, the effects of a thin chemisorbed polyaniline (PANI) film on the charge storage behavior of rod-shaped spinal-type cobalt oxide (Co3O4) nanorods (PANI@Co3O4) are detailed for fabrication of battery–supercapacitor hybrid (BSH) devices. The PANI@Co3O4 showed larger surface area and optimum porosity properties, which contributed to ∼50 % enhanced specific charge than that in the Co3O4. The deconvoluted total charge storage gain showed more contribution to the bulk-diffusion controlled process (battery-type), lower ion transport resistance and Warburg impedance in the PANI@Co3O4 electrode than that in the Co3O4. Two-sets of BSH devices are fabricated using PANI@Co3O4 as a positive electrode and mesoporous carbon (MC) and activated carbon (AC) negative electrodes in an aqueous electrolyte and benchmarked with symmetric supercapacitors fabricated using the two carbons. The PANI@Co3O4//MC device showed nearly two-fold higher specific energy (ES) than that of PANI@Co3O4//AC. Interestingly, AC//AC symmetric supercapacitors showed two-fold higher ES than the MC//MC device. Origin of differences in the charge storage behavior of the two types of devices are systematically analyzed and reported

The effect of oxygen and nitrogen functional groups on the electrochemical performance of ordered carbon

Ordered carbon (OC) has been synthesised via replication strategy by using Santa Barbara Amorphous (SBA)-15 as a template. The successful replication process has been proven by nitrogen adsorption-desorption analyzer and transmission electron microscopy (TEM). The OC showed well-aligned mesopore system, similar to the SBA-15 template. The oxygen and nitrogen functional groups introduced were identified by X-ray photoelectron spectroscopy (XPS). Electrochemical performance of the oxygen containing OC (OC-O), nitrogen containing OC (OC-N), and oxygen nitrogen containing OC (OC-ON) was then evaluated by cyclic voltammetry (CV) and galvanostatic charge-discharge (GCD) using a three electrode system in 1M KOH aqueous electrolyte. The OC-O, OC-N, and OC-ON showed significant increment in specific capacitance, CS and exhibited good capacitance retention (CR, %) over high scan rate and current density

Various Impact Resistance Capabilities of Tapioca Starch Based Shear Thickening Fluid (STF)

STF is a non-Newtonian flow behaviour often observed in concentrated colloidal dispersions characterized by significant, sometimes discontinuous increase in viscosity with increasing shear stress. Examples are concentrated particle colloidal suspensions such as photographic dies, paints, coatings and lubricants. When such fluid is subjected to a high-enough shear stress, it can lead to a rapid, sometimes discontinuous, increase in viscosity. The change in viscosity is due to the change of molecular arrangement structure in the colloidal suspension which usually will change from disordered liquid to ordered liquid crystals. Triangle Ternary Phase Diagram can be classified as a diagram that represents the equilibrium between the various liquid crystal (LC) phases that are formed between three components

Electrochemical performance of ordered mesoporous carbon modified by oxidative treatment with aqueous nitric acid

In this study, ordered mesoporous carbon (OMC) was prepared via nano-casting method by using Santa Barbara Amorphous (SBA)-15 as a template and sucrose as a carbon precursor. The OMC was subsequently oxidized with aqueous nitric acid and referred as MOMC. The physicochemical properties of OMC and MOMC were determined using nitrogen adsorption–desorption analyser, field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and Fourier transform infrared spectroscopy (FT-IR). The results proved that the carbon replication process was successful. The electrochemical performance tests were carried out using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) in 1 M KOH electrolyte for 1000 cycles. After oxidative treatment, the specific surface area and pore volume of OMC decreased but the specific capacitance of the electrode material has significantly increased from 117 F g–1 to 344 F g–1 at a scan rate of 10 mV s–1

Electrospun polyvinylidene fluoride (pvdf) blended with cellulose nanocrystals (cncs) as piezoelectric material

PVDF is a semi-crystalline polymer. Excellent thermal stability, light weight, high flexibility Sensors, actuators, transducers, energy storage, energy harvesting. Three main crystalline phases (α,β and γ) β-phase of PVDF give rise to a piezoelectric constant (electroactive state). Incorporating CNCs into PVDF to improve mechanical and electrical properties

Miniature tool for characterization of supercapacitive charge storage

A new protocol to characterize supercapacitive charge storage parameters from discharge voltage measurement and using an electrical model is presented. A distribution of capacitances and resistances in three charge storing time domains (fast, medium, and slow) are derived through this protocol. The method relieson recording the self-discharge data (open circuit discharge) and using it along with the charge redistribution within the supercapacitor to obtain the parameters for the equivalent circuit model. The results are validated using the galvanostatic charge discharge cycling. The method proposed here uses comparatively lesser number of variables, thereby making it easier to compute and the validation shows a good match between the experimental and the simulated results

Study on ionic conduction of alginate bio-based polymer electrolytes by incorporating ionic liquid

Biopolymer electrolytes is attracting a great deal of interest as a substitute for synthetic polymer electrolytes in electrochemical devices. They are carbon–neutral, sustainable, and reduce dependency on non-renewable fossil fuels, and easily biodegradable. The present work aims to develop the alginate bio-based polymer electrolytes (BBPEs) with the addition of various composition (2 to 10 wt%) of ionic liquid (1-butyl-3-methylimidazolium chloride) via solution casting technique. The ionic conduction study was characterized using electrical impedance spectroscopy (EIS) at different frequencies ranging from 50 Hz to 1 MHz. With the addition of 6 wt% 1-butyl-3-methylimidazolium chloride ([Bmim]Cl), the ionic conductivity of the BBPEs system was improved significantly from 5.32 X 10-5 S cm-1 to 2.03 X 10-3 S cm-1 at ambient temperature. The electrical properties analysis revealed that the ionic conductivity sample-based BBPEs has a good relationship with electrical properties formulism and shows non-Debye behavior where no single relaxation occurred in the present system

Pfibrolizer: A new paradigm for large scale electrospinning from lessons learnt from Malaysian kitchen

Electrospinning is a fiber production method, in which a liquid droplet is electrified to generate a jet, followed by stretching and elongation to generate fibers. Electrospinning setup mainly consists of 3 parts, a spinneret, high voltage source and a collector. The currently available electrospinning spinneret in markets has several drawbacks which limits its efficiency. Inspired from the Malaysian kitchen, we have designed a simple electrospinning spinneret head which is beneficial for large scale nanofiber production. This design also allows the user to easily modify the spinneret according to the requirements of morphology and number of fibers

"Green" -electrospun Metal Oxide Nanowires for High Performance Supercapacitors

Storage of energy under the electrochemical double layer and fast reversible redox reaction mode, which devices are known as supercapacitors, with simultaneously high energy and power densities is an active area of research recently to develop deployable clean energy devices. The transition metal oxide semiconductors such as CuO, RuO2, MnO2, etc. offers pseudo capacitance arise from an electrochemical reaction in addition to the conventional double layer capacitance; therefore, they are a preferred choice to build highly efficient supercapacitors. In this research, we have developed nanowires of a number of transition metal oxides including CuO, NiO and Co3O by a commercially viable nanofabrication technique, known as electrospinning, and studied their structural, morphological, and electrochemical properties. The nanowires of ~ 50 � 60 nm were obtained by annealing the electrospun polyvinyl alcohol fibrous mats containing a uniform dispersion of metal acetate. The supercapacitor devices were fabricated by dispersing the 70 wt.% active material in 15wt.% conducting carbon and 10 wt.% polyvinyl difluoride and pasted on a nickel foam substrate. KOH was used as the electrolyte. The specific capacitance and cycling stability of the devices were obtained from cyclic voltammetry and galvanostatic charge/discharge cycling, respectively. The devices exhibited a specific capacitance of ~620 F/g ,670 F/g and 1047 F/g for CuO, NiO and Co3O4, 4 respectively at a current density of 1 A/g in 6M KOH with a columbic efficiency of ~96%. The electrospun metal oxide nanowires could therefore be an acceptable choice for building highly efficient supercapacitor devices