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Insulation systems of electrical apparatus (fluid and solid) include transformer oil, insulating paper, glass, ceramic, mica and rubber. Normally, they are designed well to be stable at high temperatures and provide excellent electrical insulating properties in different operating loads. There is an increasing demand to modify the effectiveness and capabilities of these insulation systems to overcome various issues (e.g., overheating, overloading and short circuits). Moreover, they should match the new high voltage insulation requirements, safety, ultra-high voltage, and being environmentally friendly are some of them. Nanoparticles (NPs) are promising compensator materials that can be used to develop insulation systems with good thermophysical and dielectric properties. The results of many studies show marvelous enhancements in electrical and thermal properties. In this paper, the authors present a review that focuses on different NPs that are used in several aspects of insulation systems to improve the dielectric as well as the heat transfer properties of high voltage insulation applications. The review covers NPs types, the preparation methods, analysis approaches, different properties, performances and results, challenges, and the limitation of the use of NPs.

The photovoltaic (PV) technology has been increasingly used in our energy generation. Therefore, it is essential to have a good PV testing facility during the development process. The PV emulator (PVE) is a voltage or current source that mimic the current-voltage characteristic as a PV module that requires proper control strategy to work. The resistance feedback method (RFM) control strategy has many good attributes, except the transient response, which is caused by the proportional-integral (PI) controller. This paper proposed a new fuzzy logic PI (FLPI) controller to improve the transient performance of the RFM PVE. It is based on the error adjustment method that founded on the transient state and load of the PVE. The performance of the proposed PVE is compared with the original PVE that used RFM with the PI controller. The finding of the research shows that the transient performance of the proposed PVE has improved 2.3 times compared to the original PVE without affecting its accuracy.

The paper presents the electrochemical performance of supercapacitor with glass wool separator under organic electrolyte of tetraethylammonium tetrafluoroborate (TEABF4). The performance was evaluated using symmetrical two-electrode system and compared to an identical supercapacitor with commercially available cellulose paper separator under 1 M TEABF4. The application of glass wool separator reduces the bulk resistance of supercapacitor by 19.6%, promotes more efficient ions transfer across active surface of electrode and significantly improves specific capacitance by 19.1% compared to cellulose paper. The application of higher concentration TEABF4 (1.5 M) even improves the overall performance of glass wool-based supercapacitor by 32.2% reduction of bulk resistance and 61.9% increment in specific capacitance compared to 1 M TEABF4. In addition, the energy and power densities are significantly improved by 64% and 165%, respectively for the one with 1.5 M TEABF4. In general, the low-cost material glass wool material has great potential to replace commercially available cellulose paper as separator in developing much better supercapacitor.

This paper investigates the effects of thermal aging on unfilled polypropylene (PP) and PP containing 1 wt% of magnesium aluminate (MgAl 2 O 4 ), calcium carbonate (CaCO 3 ), and surface modified calcium carbonate (CaCO 3 T) nanofillers. Two different aging conditions were considered, i.e., unaged (20 °C) and aged (140 °C). The structures of the evaluated samples before and after aging were observed using scanning electron microscopy (SEM). In addition, thermal stability and electrical properties were evaluated by means of thermogravimetric analysis (TGA) and DC breakdown testing. The results showed that the structure of all investigated samples was less susceptible to thermal aging. Meanwhile, the thermal stability of the unfilled PP has reduced significantly than that of nanocomposites. Besides that, the electrical breakdown strength of both the unfilled PP and PP nanocomposites containing 1 wt% of MgAl 2 O 4 , CaCO 3 , and CaCO 3 T nanofiller has reduced compared to the respective unaged samples. Of note, nanocomposites were less susceptible to changes in DC breakdown strength after thermal aging.

The electrochemical properties of supercapacitors with kenaf-derived activated carbon electrodes under different activation time durations were evaluated. The study aims to determine the optimum activation time required that contributes to highest supercapacitor’s perfomance. Kenaf fibre was firstly carbonized at 400 °C to remove its water content and any volatile substances. The resulted kenaf-derived carbon was then impregnated in potassium hydroxide (KOH) with 4:1 impregnation ratio and left overnight. After the impregnation process, the carbon sample was activated at 600 °C with different heating time durations of 1, 2, 3 and 4 hours and named as A600-1, A600-2, A600-3 and A600-4, repectively. Four supercapacitors with the kenaf-derived activated carbon samples as the electrodes were fabricated based on two-electrode symmetrical test cell system. Specific capacitances of 108, 189, 242, and 126 F/g for supercapacitors with activated carbon A600-1, A600-2, A600-3 and A600-4 electrodes, respectively were achieved. These were much higher than previously reported values of only up to 37 F/g. The finding suggests that an inexpensive fibrous carbon material derived from kenaf by a facile pyrolysis process may be a remarkable choice to construct high performance supercapacitor.

Even though natural insulating oils (NEI) oils are environmentally friendly, these oils have not gained widespread use in high-voltage oil-immersed power transformers because of their unfavorable properties such as low pour point, low oxidation stability, low resistance to lightning impulse, and high kinematic viscosity. Hence, much effort has been made to overcome the disadvantages of NEI oils, including the addition of additives, modification of the chemical structure of oils and altering the transformer design to ensure compatibility with the oils. This review article is focused on the methods used to improve the workability of NEI oils in power transformers, namely, (1) depression of the pour point, (2) chemical modifications, (3) changes in the transformer design, (4) addition of nanoparticles, (5) addition of lightning resistance additives, and (6) addition of antioxidants. The benefits and challenges of each method are also discussed. It is believed that this review article offers new insight to scientists and researchers in this field.

The characteristic of battery that has low power capacity cause the overall performance of an electric vehicle (EV) with single energy supply is not optimal. Thus, the EV system need to uses a battery as a primary energy source and combined with a supercapacitor that acts as a buffer system to provide a desired power to the load. However, the power that being supplied by both battery and supercapacitor must be controlled to prevent a high current drawing from the battery. This paper investigate the impact of controlling hybrid energy storage system (between battery and supercapacitor) to the lifetime of battery in EV. Both energy sources are interfaced with a unidirectional/bidirectional DC–DC converter. The MATLAB simulations are carried out to analyze the state-of-charging (SOC) for the battery and supercapacitor for a random driving cycle. The results show that the highest SOC in battery can be achieved when the multiplier in energy limiter is set to 100% and followed by 70% and 50%. The supercapacitor still able to fulfill the remaining load after completed the 14 seconds of run time. Thus, with the knowledge on maximum energy limiter that can be set on controlling hybrid energy storage system, the lifetime of the battery can be extended and the performance of EV can be improved.

A Taguchi-based methodology is proposed in this study in order to determine the optimum concentration of antioxidants which will enhance the oxidative stability of natural ester insulation (NEI) oil while ensuring superior dielectric strength performance. Conventional experimental testing involves the procurement of materials and equipment, sample preparation, experimental set-up and testing the samples with a large number of test runs to determine the optimum design parameters, which is costly and time-consuming. In this regard, the Taguchi-based methodology is advantageous since it can predict the optimum design parameters with fewer test runs. This methodology can also be used for multi-response optimization by applying a desirability function. The number of test runs for the antioxidant mixtures is generated using the L 9 orthogonal array with three levels and two factors. This methodology limits the need to deal with the uncertainties associated with the range of factors, unlike the one-factor-at-a-time (OFAT) method. The oxidative induction time (OIT) and AC breakdown voltage (AC BdV) are selected as the output responses in accordance with the ASTM E1858 and ASTM D1816 standard test method, respectively. Analysis of variance (ANOVA) is used to determine the percentage contribution of each factor as well as the significance level of the model developed from the Taguchi-based methodology. The desirability function is used to transform the two output responses and generate the optimum value which complements both of the responses. Repeated tests are conducted to verify the repeatability and reproducibility of the OIT and AC BdV results for the optimized NEI oil based on a 95% confidence interval. In general, there is a significant enhancement in the OIT and AC BdV for the optimized NEI oil compared to those for fresh NEI oil. Hence, it can be concluded that the Taguchi-based methodology is a feasible approach to determine the optimum concentrations of mixed antioxidants for NEI oils.

Natural ester insulation (NEI) oils have been developed since the early 1990s due to the increasing environmental, health and safety concerns from the public. NEI oils are well-known for having high fire and flash points, great moisture tolerance, good biodegradability and non-toxicity. However, NEI oils also have several drawbacks compared to mineral insulation (MI) oils such as low oxidative stability, high viscosity, low pour point and low resistance towards lightning impulse. Previous researchers have discovered that the oxidative stability of NEI oils can be improved by the addition of mixed antioxidants. However, such studies are focused on only one criterion and they neglect the dielectric strength of the oils. On the other hand, the one-factor-at-a-time (OFAT) method is commonly used to determine the optimum concentration of mixed antioxidants and requires a large number of samples. In this study, response surface methodology (RSM) technique is used to determine the optimum concentration of mixed antioxidants which will enhance the oxidative stability of NEI oil. The dielectric strength of the NEI oil is evaluated based on the AC breakdown voltage (BdV). RSM is chosen in this study because it is capable of determining the optimum values of the parameters of interest, without the need for a large number of test runs which will incur high cost for experimentation. A regression model is developed in this study based on the AC breakdown voltage of the NEI oil, propyl gallate and citric acid antioxidant concentrations. The oxidative induction time (OIT) and partial discharge inception voltage (PDIV) are carried out to determine the effect of the oxidative stability and withstand voltage on the partial discharge, respectively. The results showed that there is enhancement in the oxidative stability and dielectric strength of NEI oil using the optimum concentrations of mixed antioxidants relative to the fresh NEI oil. It can be concluded that RSM is a feasible alternative to determine the optimum concentration of antioxidants for NEI oils, which in turn, helps improve the oxidative stability and dielectric strength of these oils.

Activated carbon (AC) prepared by two-stage microwave-induced physical activation of oil palm shell have been coated using electroless plating technique to form nanocomposite material. The composite materials were calcinated at different temperature of 300, 400 and 500 °C for one hour. The nanocomposite materials were evaluated as potential electrodes for supercapacitors. Using the composite electrodes in a two-electrode symmetrical capacitor, the properties of the composite electrodes were investigated by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS). Results from electrochemical measurements show that the nanocomposite electrodes exhibit superior capacitive performance compared with the AC electrode. The specific capacitance have been found to increase by 85–205% with respect to the AC electrode. In addition, the specific capacitance as well as the energy density were found to reduce with the increment of the calcination temperature. The composite electrode calcinated at 300 °C offers the maximum enhancement of 205% in both specific capacitance and energy density.

The use of multi-level inverters is increasing in different structures, high power and medium power applications due to advantages such as low switching losses, harmonic distortion and electromagnetic interference at the output which could be used in microgrid systems. A microgrid can be defined as groups of renewable energy sources such as photovoltaic and wind turbine i.e. The switching technique for inverter control plays a significant role in reducing or eliminating the harmonics of inverter output voltage and reducing the switching losses. To minimize the distortion of the output voltage of the cascaded H bridge multi-level inverter due to low-order harmonics, an optimization method used for frequency selection, i.e. the carrier wave amplitude in the SPWM strategy within this study. The proposed method is called OSPWM, which employs a new optimization method based on the Salp swarm algorithm. The proposed method applied to a cascade H bridge five-level inverter. The simulation results show the reduction of the low-frequency harmonics amplitude and THD output voltage by optimizing the OSPWM carrier wave parameters with the optimization algorithm. The proposed method also compared with the classical SPWM method.

The paper evaluates noncorrosive and inexpensive materials, namely polypropylene sheet, fiberglass, and glass wool, as potential separator materials for electric double-layer capacitor (EDLC) application. Using these materials as separators and the same activated carbon electrodes, properties of two-electrode capacitors filled with aqueous sulfuric acid (H2SO4) were investigated by cyclic voltammetry (CV) as well as galvanostatic and electrochemical impedance spectroscopy (EIS) measurements. Performance comparison of the tested capacitors with an identical capacitor with conventional cellulose separator was also carried out. As a benchmark, the noncorrosive-separator-based capacitors demonstrate comparable power and energy densities to those of a cellulose separator, with the highest specific capacitance of 131 F/g and lowest equivalent series resistance of 13 Ω for the glass wool separator. Application of such noncorrosive separators may realize the utilization of high-concentration aqueous electrolytes, leading to higher rating EDLCs at lower cost compared to organic-solution-based capacitors. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

The paper evaluates the electrochemical performance of glass wool as an alternative separator material for electric double layer capacitor (EDLC) construction. Using aqueous solution of sulfuric acid as the electrolyte, two-electrode coin-type capacitors were constructed by sandwiching the electrolyte-containing glass wool with two activated carbon sheets. Electrochemical properties of the capacitors were characterized by cyclic voltammetry, galvanostatic and impedance spectroscopy measurements. The glass wool-based capacitor outperforms the practically used cellulose separator with higher power and energy densities of 566 W/kg and 15 kJ/kg, respectively. The implementation of glass wool separator will enable the utilization of high concentration aqueous electrolytes, which lead to higher rating EDLC at relatively lower cost compared to organic solution-based capacitor.

Over the years, solar has been one of the main substitutes of electricity resources worldwide including Malaysia in effort to reduce the dependency on the conventional fossil fuel. In this paper, the status of solar energy in Malaysia Plans is investigated while the techniques used in various techno-economic and economic feasibility studies on the implementation of solar energy system are analyzed. The state of awareness and understanding on solar energy among Malaysians is also determined. It has been found that a mathematical formulation method as well as an iterative technique which both consider lots of uncertainties are capable in optimally designing a photovoltaic, PV system while minimizing the cost. Meanwhile, a financial model using probabilistic and sensitivity analysis is able to provide the potential investors with the profitability of a PV project. Finally, several surveys has proven that Malaysian people are lack of awareness, information thus interest on solar technology. Therefore, in eval...

The paper presents the electrochemical impedance behavior of recently introduced corrosive resistant material for supercapacitor's separator; glass wool under four different concentration of 0.5, 1, 5 and 18 mol/dm3 sulfuric acid (H 2 SO 4 ) electrolytes. Ultracapacitors with a pair of activated carbon sheets as the active electrodes and each electrolyte-containing glass wool as the separator were constructed in a custom-made two-electrode test cell. The electrochemical impedance was carried out within the frequency range of 1 mHz to 100 kHz. The impedance data were extracted into a typical Nyquist plot, complex capacitance and complex powers in order to thoroughly evaluate the supercapacitors performance in terms of their specific capacitance, associated resistances, relaxation time and power capacity. Appealingly, as compared to the lower concentrated electrolyte-based supercapacitor, the supercapacitor with 18 mol/dm3 H 2 SO 4 electrolyte has outperformed others with 18% increment of specific capacitance, 57% enhancement of relaxation time and 63% reduction of internal series resistance. Overall, the electrochemical impedance behavior of the glass wool-based supercapacitors approach closely to an ideal capacitive characteristic under various H 2 SO 4 concentration, indicating its high potential to be applied in higher performance supercapacitor construction.

Electric vehicle (EV) had the potential for helping to create a more sustainable future as it powered by green technology battery. Therefore, the investigation on battery performance has gained a lot of attention since it is one of advanced technology storage element. This paper reviews an analysis of the relationship between the acceleration of electric vehicles and state-of-charging (SOC) of battery in EV. The energy storage capacity reduction in the battery is inversely proportional to the acceleration rate. As the driving cycles and acceleration rate changing will influence the time taken for the battery to reach 0% of SOC. Several random driving cycles are created in order to identify its relationship with SOC. At the end of this paper, a mathematical equation is introduced to represent the relationship between acceleration rates versus SOC of EV.

The paper evaluates the charge-discharge cyclability of ultracapacitor with glass wool separator under various concentration of aqueous sulfuric acid (H 2 SO 4 ) electrolytes. For lower concentrated electrolyte of 1 mol/dm3 H 2 SO 4 , the performance was compared to an ultracapacitor with conventional cellulose separator. Two-electrode ultracapacitors were constructed by sandwiching two activated carbon electrodes with each electrolyte-containing separator material. The cyclability test was performed with constant charge-discharge current of 10 mA for up to 300 cycles. Prior to the cyclability test, the constructed ultracapacitors were evaluated based on cyclic voltammetry and galvanostatic tests. The glass wool-based capacitor has performed comparably to the conventional cellulose-based capacitor in terms of its specific capacitance and internal resistance for up to 300 cycles. Interestingly, in a higher concentrated electrolyte of 18 mol/dm3 H 2 SO 4 , the specific capacitance of the glass wool-based ultracapacitor is 40% greater than of 1 mol/dm3 H 2 SO 4 electrolyte. It is envisaged that by applying the glass wool as the separator coupled, with high concentration aqueous electrolyte may lead to higher rating ultracapacitor at relatively lower cost as compared to an organic electrolyte-based ultracapacitor.

The paper evaluates the essential electrical properties—capacitance and equivalent series resistance (ESR)—of hydrocarbon-derived electrolytes for supercapacitors using galvanostatic, constant resistance charge–discharge, cyclic voltammetry, and AC impedance measurements. The electrolytes were systematically prepared from six hydrocarbon-derived compounds, which have different carbon chains and functional groups, with the treatment of concentrated sulfuric acid (H2SO4). Both electrical properties seem to be in conformity throughout these measurements, with the longer main carbon chain compounds giving higher capacitance and lower ESR values. Comparison between these electrolytes and the typically used aqueous solutions in supercapacitor research—1M H2SO4, 5M potassium hydroxide, and 5M sodium hydroxide—showed that the produced electrolytes give the highest capacitance value up to 30 times more than that of typical aqueous solutions. It is believed that with further treatment these hydrocarbon-derived electrolytes can potentially be used in supercapacitors as better performing electrolytes than aqueous solutions and at a relatively low cost compared to organic solutions. IEEJ Trans 2011 DOI: 10.1002/tee.21802

In this study, the Taguchi method is used to optimize the in-lab reclamation process parameters of used transformer oils. The main benefit of this method is that one can determine the optimum parameters of the reclamation process in a simple, efficient, and cost-effective manner. The L4 (23) Taguchi design is used to optimize the following process parameters: (1) weight of the Fuller’s Earth adsorbent, (2) stirring speed, and (3) oil temperature. These parameters are optimized in order to minimize the AC breakdown voltage, total acid number, and dynamic viscosity of the reclaimed transformer oil samples. The signal-to-noise ratios are determined for each process parameter in order to identify the significance of each factor on the three output responses. Based on the results, the oil temperature has the most significant effect on the AC breakdown voltage whereas the weight of the Fuller’s Earth adsorbent has the most significant effect on the total acid number and dynamic viscosity of the reclaimed transformer oils. Tests are carried out to verify the results using the optimum reclamation process parameters and indeed, it is found that there is significant improvement in the mean AC breakdown voltage, total acid number, and dynamic viscosity for the reclaimed transformer oil compared with those for the used transformer oil. It is believed that this method can be an indispendable tool to determine the optimum parameters for the reclamation process without going through the hassle of trial and error associated with conventional experimentation.

Power transformers are the backbone of electricity transmission and distribution systems throughout the world. The price of power transformers is exorbitant (costing millions of dollars per unit) and therefore, frequent maintenance is necessary to ensure that these systems are highly reliable during their operation. The service life of mineral insulating oils is typically 30 to 40 years for power transformer applications. However, all insulating oils (regardless of their type) are subjected to thermal, electrical and chemical degradation, which will deteriorate the oil-paper insulating system and consequently reduce the capability of the oil as an electrical insulator. For these reasons, service-aged insulating oils are treated by two types of processes (i.e. reclamation and reconditioning) in order to prolong the service life of these oils. Reclamation (regeneration) is used to treat insulating oils with high levels of acidity and sludge. In this paper, a brief review on the reclamation technologies used to treat service-aged insulating oils is presented, covering various aspects such as the standard test methods that need to be complied with, the types of adsorbents used to reduce acidity and sludge of the used insulating oils, as well as the findings of several key studies related to the evaluation of the effectiveness of the reclamation process. This review will indeed benefit researchers and practitioners in this field since it provides an overall picture of the recent progress in reclamation technologies for service-aged transformer insulating oils

Tenaga Nasional Berhad (TNB) is a power utility company in Malaysia that performs three main thrust in the electricity sector. One of which is the distribution sector. The distribution sector involves other activity associated with the customer. Many initiatives have been introduced by TNB to satisfy all its customers. This research introduces a method of reading electric meter without sending meter readers to the premises of the customers. This method was introduced to large power customers (LPC) to ensure total consumption recorded is accurate. Since 2005, remote metering reading project has been using global packet radio service (GPRS) technology as a medium of communication. However, GPRS communication system at that time has not been widely used. Use of electronic meters is introduced to LPC because this meter can provide current information about electricity consumption. A total of 45,000 users of LPC involved in the installation of electronic meters and global system for mobile communication (GSM) modem in which this system can determine the amount of electric current consumption compared to manual meter reading is applied. In this project, the XBee radio module is used to send data to a GSM modem. From GSM modem, users can get the total electricity consumption through the SMS (short message service) system in their mobile phones. This project aim is to facilitate the customers so that they do not have to waste time going to the Kedai Tenaga (electricity payment counter) to find out the amount of energy consumed during the period. TNB can also collect the metering details without sending personnel to produce monthly bills.

Recently, natural ester insulation (NEI) oils are found to be the best candidates to replace mineral-based insulation oils for oil-immersed transformer applications. However, NEI oils are prone to oxidation due to their poor oxidative stability which can be improved by adding antioxidants into the oils. Latest studies have also shown that the use of selected antioxidants improves the AC breakdown voltage (BdV) of NEI oils. However, the experiments in previous studies were designed using the conventional one-factor-at-a-time (OFAT) method, which requires a large number of samples to be tested in order to determine the optimum response. Thus, a Taguchi-based designed experiment is introduced in this study in replacement of the OFAT method. It is found that this method is capable of determining the optimum concentrations of propyl gallate (PG) and citric acid (CA) which will maximize the AC BdV and improve the oxidative stability of the NEI oil. An AC breakdown voltage test is conducted in accordance with the ASTM D1816 standard using Megger OTS60PB portable oil tester, in which the electrode gap distance is kept fixed at 1 mm. The results indicate that the addition of PG and CA antioxidants increases the AC BdV of the rapeseed-based NEI oil. It is found that the optimum concentrations of PG and CA antioxidant is 0.05 and 0.25 wt.%, respectively. Lastly, the model developed in this study is analysed using analysis of variance (ANOVA). Validation test is also conducted on the optimized NEI oil to determine its dielectric strength and oxidative stability.

Recently, many studies have been conducted on the dielectric properties of Low-Density Polyethylene (LDPE) nanocomposites and produced different results. However, the composition of LDPE polymer and boron nitride (BN) as nanofiller has neither been well understood nor producing a convenient result. Similarly, the dielectric spectroscopy measured at “sub–hertz” frequency has been of little interest among researchers since it is often influenced by “conduction-like” effect. This research identified the dielectric properties of LDPE nanocomposites filled with hexagonal boron nitride (h-BN) nanofillers by using dielectric spectroscopy technique. The dielectric loss and relative permittivity for three different filler concentrations were investigated under “sub-hertz” frequency ranges at room temperature. The cylindrical electrode with guard ring configuration was used to conduct the experiment, in accordance to the ASTM D150 standard. The results revealed that 5 wt% filled polymer has lower loss tangent and permittivity compared to the unfilled polymer, due to the strong interaction between nano-particle and the polymer. This strong interaction is believed to limit the movement of the polymer chain. The decrease in loss tangent also indicates lower quasi-DC at low frequency. However, further increase in the filler loading has recorded an increment in the value of permittivity and loss tangent. This higher effective permittivity is mainly due to the influence of the filler permittivity.

Terahertz (THz) spectroscopy has high sensitivity for the interaction between molecules and vibration of large molecules. Besides, it is well known that infrared (IR) spectroscopy can be used to detect the vibration of functional groups. Hence, the comparison of the conventional diagnosis method using IR spectroscopy and THz spectroscopy is expected for more potential diagnosis. In this study, the comparison between THz spectroscopy and IR spectroscopy for deteriorated hydrocarbon liquids has been conducted for the degraded insulating oils. The surveyed samples are pure dodecane and mineral oil. The degraded samples are made by heating in the oxygen atmosphere. In addition, we also measured the breakdown voltage and the volume resistivity to know the states of degraded insulating oil. The experimental results show that oxidation causes spectral changes in the both of THz and IR regions. The spectral change in the IR region is due to carbonyl group and hydroxyl group vibrations. Whereas, in the THz region, the spectral change originates from the modification of intermolecular interaction. The degradation phenomena of the insulating oil contribute to higher carbonyl/hydroxyl content and associated by stronger intermolecular interaction that leads to its lower breakdown voltage.

This paper describes the electric properties of new carbon materials derived from the chemical synthesis mixed with insulation oil or lubricating oil and sulfuric acid. New carbon material as an activated carbon has higher capacitance expecting for large electric energy storage system. The capacitance and internal resistance were measured as a function of mixture ratio of the materials using the capacitor model. Experimental results show that the new carbon material has a high potentiality for large electric energy storage systems.

The need of energy storage device with higher rating for wider application range has led to a great interest among engineers and researchers in proposing better materials for the device electrodes. The paper reports our current research progress in developing a new higher rating energy storage device like an electric double-layer capacitor (EDLC). New microporous carbons were systematically prepared by chemical reaction between mineral oil and strong acid, sulphuric acid, in various compositions. The graphitic nature of the produced microporous carbons were characterized by X-ray diffraction (XRD) measurement. Essential electrical properties of the microporous carbons for energy storage application, such as their capacitive behavior, were investigated by cyclic voltammetry measurements. In order to observe the frequency characteristics of the microporous carbons, one of the most important analytical tools known as electrochemical impedance spectroscopy was used. The experimental results of the XRD and electrochemical measurements are presented in forms of graphical plot.

In this paper, we evaluate the essential electrochemical properties – capacitive and resistive behaviors – of hydrocarbon-derived electrolytes for supercapacitor application using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The electrolytes were systematically prepared from three hydrocarbon-derived compounds, which have different molecular structures and functional groups, by treatment with high-concentration sulfuric acid (H2SO4) at room temperature. Two-electrode cells were assembled by sandwiching an electrolyte-containing glass wool separator with two active electrodes of activated carbon sheets. The dc electrical properties of the tested cells in terms of their capacitive behavior were investigated by CV, and in order to observe the frequency characteristics of the constructed cells, EIS was carried out. Compared with the tested cell with only high-concentration H2SO4 as the electrolyte, the cell with the derived electrolytes exhibit a capacitance as high as 135 F/g with an improved overall internal resistance of 2.5 Ω. Through the use of a simple preparation method and low-cost precursors, hydrocarbon-derived electrolytes could potentially find large-scale and higher-rating supercapacitor applications.