Supercapacitor Storage Research Articles

Study of Peat Fillers for their Potential Use in Electric Energy Storage Devices

The article discusses the pros and cons of modern devices for power accumulating and its storage (supercapacitors). The author analyses porous carbon materials traditionally used as fillers in such devices. The presented main physical and chemical properties of peat allow the author to propose a working hypothesis about the possibility of using peat sorbents in supercapacitors. This is possible due to the high specific surface area of peat and by the presence of particles with a double electric layer (micelles) in it. For the first time ever, it was experimentally established that the use of a bog peat sorbent instead of activated carbon as a porous material makes it possible to multiply the voltage during self-discharge of an experimental model of a supercapacitor. The size of the peat sorbent fractions does not significantly affect the self-discharge process. However, there is a slight improvement in the performance of the device when using the fractions under 1.25 mm. The use of peat raw materials with a high degree of decomposition significantly improves the characteristics of the experimental model at a charging voltage of 10 V.

Musa paradisiaca reduced graphene oxide (BRGO) /MWCNT-Fe3O4 nanocomposite for supercapacitor and photocatalytic applications

This paper reports novel eco-friendly reduction of GO to RGO (BRGO) by Musa paradisiaca extract for choice in many areas of application. However, the layer by layer tight stackin in their thin film form inevitably diminishes the interlayer space between homogeneous ultrathin nanosheets, which could significantly hinder the electrolyte diffusion. Herein, Fe3O4 nano particles are uniformly dispersed on MWCNT with the less agglomeration and then fabricated composite with BRGO for energy storage (supercapacitor) and water remediation (photocatalytic) application. After preparation, the BRGO Fe3O4-MWCNT nanocomposite was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), UV–Visible spectroscopy (UV), transmission electron Microscopy (TEM) and scanning electron microscope (SEM) analyses. The electrochemical behaviour of the material was analysed by cyclic voltammetry (CV), galvanometric charge–discharge (GCD) study and impedance spectroscopy. The photocatalytic degradation was carried out in a photocatalytic chamber. The synthesized nanocomposite exhibited a high specific capacitance value of 165 F/g at 2 A/g and also showed good photo degradation efficiency on the methylene green dye (MG), which is higher than the degradation efficiency of other individual materials like Fe3O4-MWCNT and BRGO. The prepared nanocomposite was found to have good cyclic stability in the capacitance study and it mineralizes the organic dye to an extent of 94%. BRGO-Fe3O4-MWCNT as effective nanocomposite for application as advanced supercapacitor electrode and developing novel photocatalyst for remedy of environmental problems.

Improving the Transient Response of Hybrid Energy Storage System for Voltage Stability in DC Microgrids Using an Autonomous Control Strategy

In renewable microgrid systems, energy storage system (ESS) plays an important role, as an energy buffer, to stabilize the system by compensating the demand-generation mismatch. Battery energy storage system serves as a decisive and critical component. However, due to low power density and consequently slow dynamic response the lifetime of BESS is observably reduced due to high current stress, specifically experienced during abrupt/transient power variations. Hence, hybridization with supercapacitor storage system is conferred. Additionally, the controllers designed for energy storage systems should substantially respond for compensating the transient requirement of the system. In this article, we propose a decoupled control strategy for batteries and supercapacitors based on k - Type compensators and a nonlinear PI controller (NPIC) respectively. The formulated control design is tested for voltage regulation in a standalone microgrid. Furthermore, a comparative analysis is presented with benchmark low-pass-filter (LPF) based controller. The results obtained shows the proposed control technique possess a faster response with improved voltage regulation capabilities. For the test system regulated at 48 V for various abrupt load-generation various case studies presented, the proposed methodology maintains a significantly reduced voltage deviation between 47 V - 51 V in contrast to 45 V - 56 V observed in the LPF methodology. Furthermore, the complexity is simpler in comparison to LPF based control strategy and a comparative obviation of additional sensing devices is achieved, that inherently reduces the detrimental effect on ESS response during transient condition.

Design and testing of a supercapacitor storage system for the flash recharge of electric buses

This paper proposes a hybrid storage for urban transport systems in order to reduce recharge time and increase its life and reliability. Proposed system is applied to a pre-existing electric vehicle, introducing through proposed revamping procedure a methodology for a fast integration of proposed systems on different vehicles. Finally, the system is calibrated and tested showing how the proposed control layout really simplifies the vehicle commissioning.

Design and testing of a supercapacitor storage system for the flash recharge of electric buses

This paper proposes a hybrid storage for urban transport systems in order to reduce recharge time and increase its life and reliability. Proposed system is applied to a pre-existing electric vehicle, introducing through proposed revamping procedure a methodology for a fast integration of proposed systems on different vehicles. Finally, the system is calibrated and tested showing how the proposed control layout really simplifies the vehicle commissioning.

Design and control of a DC microgrid by using a modern predictive controller

In this paper, a hybrid energy storage system (HESS) and its control strategy are designed and analyzed for a dc grid. HESS is used to maintain the constant dc grid voltage due to the changing power surges. The batteries' storage system and super-capacitor (SC) are used to balance the slow-changing surges and fast-changing surges. A decrease in conventional energy sources has led to cost-effective renewable power sources. The utilization of these resources reduces the fuel cost to a great extent. In remote areas where the primary utility grid is not feasible, the standalone renewable generation can offer more benefits. Due to the varying nature of the load, demand can control the hybrid renewable energy system is required. To maintain the stability, power flow control, and power-sharing between the battery and SC requires the energy management system. Currently, the battery storage system seems to solve the load demand and power generation fluctuations in real-time power systems. The paper proposes a Modern Predictive Controller (MPC) for a hybrid energy system. It is based on the decoupling of different frequency components and utilized error signals of battery current to control the SC and faster voltage regulation and reduced current stress on the battery.

Proposed energy management for a decentralized DC-microgrid based PV-WT-HESS for an isolated community

Microgrids are small-scale power systems destined to supply isolated villages and optimum utilization of renewable energies. For this reason, this paper presents a DC-MG of 150 Kwp to feed an island village. The configuration of the proposed system consists of four interconnected sub-sections supplied by the centralized unit through PV and Wind Distributed Energy Resources DERs, in addition to the supercapacitor storage device. In the other hand, internal batteries of each sub-section cover its load demand separately, where electrical and chemical storage devices can be advantageous hybrid energy storage system HESS for the system. Thus, the control structure of the DC-MG is based on current hysteresis method to assure the charge/discharge operation and the stability of the DC-bus voltage, then a proposed management strategy to manage the shared energy of the DCMG system. The system behavior is tested under variable parameters and conditions using Matlab/Simulink.

Hybrid four‐level FC inverter using an internal supercapacitor storage system for a microgrid connected application

In this study, a new topology of grid-connected four-level inverter is introduced. The proposed structure, based on intermediate supercapacitors energy storage, is introduced to ensure two operation modes: to provide power to a microgrid from renewable energy sources and to regulate its voltage during short-term power disturbances. The main idea is to replace ordinary capacitors of a four-level flying capacitor (FC) inverter by supercapacitors and operate them under variable voltage conditions. The control strategy applies linear matrix inequalities approach as well as space vector modulation technique to generate the appropriate switching states. The latter part of this study is dedicated to the redundant state selection method for supercapacitors voltages balancing. Through experimental implementation, presented results highlight the efficiency of the proposed hybrid inverter in ensuring microgrid stability.

Cost-Effective and Eco-Friendly Carbon-Based Nanomaterials in Wearable Energy Storage Devices

The growing concerns of pollution and subsequent climate change have garnered researchers and enthusiasts all over the world to strive forward towards a sustainable and renewable energy economy. Nevertheless the energy production is not sufficient enough until, it is stored and utilised adequately. Henceforth, the electrochemical energy storage devices such batteries and supercapacitors have find a prominent place in the list. Quite recently, wearable energy storage devices can be a game changing for the energy storage industries. Thus, the search of competent electrodes for potential device is incalculable. The nanomaterials based electrodes are attracting the interest of scientist because of their efficient capacity in energy storage.In the nanomaterials, the physical and chemical properties can be extensively tuned by parameters such as morphology, distributions, composites etc. Besides that the electrolyte in an energy storage device also plays a vital role for the operating potential and cycle life of the device. The conductive electrolyte provides pathway for easy ion movements during charge and discharge of device. The carbon-based nanomaterials such as graphene, carbon quantum dots, activated carbon etc., can be used as negative electrode. These can be also used as positive electrodes when composite with some metal oxides, hydroxides or sulphides. These electrode materials can be synthesised by chemical methods or by carbonising the natural products such as dry leaves, fruits, peals, milk etc. Most interesting process to extract carbon is recycling the wastes viz., tyres, shoot, dry cells etc. to have an eco-friendly environment. Thus realize highly stable device, the development of carbon-based electrode materials is imperative. In this work, generation of efficient carbon-based electrodes by recycling of waste for energy storage devices will be presented in details.The wearable energy storage devices are emerging area for future electronics technology. Wearables are not just a smartwatch, but a whole range of wearable devices, including biosensors, biomedical equipment, renewable charged devices etc. These devices have tremendous potential to improve quality of life and safety. Researchers and industries are involved in developing carbon-based electrodes for wearable sensors and self-powered devices to create a new generation of wearables with high outcomes to meet the consumer demand. Henceforth, the generated carbon-based materials can be potential electrodes in wearable energy storage devices.Key words: Nanomaterials, Recycling, Carbon, Energy, Wearable Electronics, Capacity

Phosphorus-doped cobaltous oxide core@shell microspheres with enhanced performances in energy conversion and storage

Nowaday, developing sustainable energy storage and conversion techniques is of great desire to alleviate energy demands and environmental pollution, in which the core issue is to develop cost-efficient, high-performance and sustained electrode materials. Herein, we proposed a cost-efficient strategy by integrating solvothermal technique, calcination and up-stream gas method to fabricate bifunctional phosphorus-doped CoO core@shell microspheres, which perform great in both energy conversion (hydrogen evolution reaction) and energy storage (supercapacitor). Due to core@shell structure and phosphorus doping, the resulted P–CoO core@shell structures possess high specific surface area, enhanced conductivity and additional active sites. As a result, the P–CoO exhibits excellent electrocatalytic HER performances in alkaline media with a low overpotential (143 mV at 10 mA/cm2) and long-term stability (more than 24 h). Meanwhile, the prepared material presents greatly improved supercapacitive properties with ultrahigh capacitance (1845 F/g at 1 A/g) and excellent cycling stability. Therefore, this strategy provides a new contribution to develop multifunctional electrochemical-active materials for energy conversion and storage.

Characterization of Molecular Spacer-Functionalized Nanostructured Carbons for Electrical Energy Storage Supercapacitor Materials

The use of molecular spacers between Carbon Nanotubes (CNTs) has been shown to increase the ion-accessible surface area for use in supercapacitor materials. Maintaining porosity and electrical conductivity is important for maximizing capacitance, energy storage, and power. Two reported novel coordination complexes have shown exceptional Faradaic charge transfer and binding capabilities to prevent CNT aggregation. Dispersion stability measurements show less aggregation of HiPco Single Walled CNTs (SWCNTs) compared to other chirality and multilayered nanotubes. Cu2FcOH binds weakly to CNTs compared +2Zn2 and +2Ru2 due to Columbic electrostatic interactions, which is favorable because it does not collapse the electrical double layer as strongly as +2Zn2 or +2Ru2. Adsorption isotherms and a full characterization (1H NMR, ATR FT-IR, UV-Vis, CV) of these novel complexes are presented. Electrical characterization using CV, charge discharge, and electrochemical impedance spectroscopy and the supercapacitor performance of functionalized thin film electrodes are presented as a function of spacer properties and nanostructured carbon tube diameter. This study uses rigid, earth-abundant coordination complexes that bind to and intercalate between SWCNTs. These functionalized nanostructured carbons are then used to make electrodes for electrical double layer supercapacitors. A complete description of the synthesis, characterization, and processing of these materials is described.

Synthesis of Mn3O4 nanoparticles via microwave combustion route for electrochemical energy storage application

Abstract In the present article, the synthesis of manganese oxide (Mn3O4) nanoparticles (NPs) have been achieved by microwave assisted combustion method, which was further investigated for an electrode material in supercapacitors. The as-synthesized Mn3O4 nanoparticles were characterized by different techniques like powder X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), UV–Visible spectroscopy etc. XRD pattern reveals a crystalline, tetragonal phase of Mn3O4 (hausmannite) nanoparticles with a crystallite size of 28.08 nm. SEM image shows that the Mn3O4 nanoparticles are present as spongy aggregates. From Tauc plot, the band gap of the material was found to be around 1.97 eV, which is suitable for energy storage (supercapacitor) application. Investigation on the electrochemical properties of Mn3O4 nanoparticles were carried out by using Cyclic Voltammetry (CV) and galvanostatic/ potentiostatic charge-discharge studies. The results signify that the obtained Mn3O4 nanoparticles can be used as a potential electrode material for supercapacitor applications.

Reduced graphene oxide decorated CoSnO3@ZnSnO3 with multi-component double-layered hollow nanoboxes for high energy storage and capacity retention asymmetric supercapacitors

Double-layered hollow nanostructure composed of CoSn(OH)6@ZnSn(OH)6 which are derived from CoSn(OH)6 nanoboxes wrapped by ZnSn(OH)6 cover layers is prepared by a controlled alkali etching method, followed by heating treatment to prepare reduced graphene oxide (rGO) decorated CoSnO3@ZnSnO3 nanoboxes. The results revealed that the specific surface area of CoSnO3@ZnSnO3 reached 70.29 m2 g−1, which is much higher than that of CoSnO3 (44.25 m2 g−1). The enlargement in specific surface area of the double-layered hollow structure can responsible to provide sufficient buffer space for the dramatic volume change during the cycle. Moreover, rGO can effectively promote the transmission of ions or electrons and can provides a large reaction interface for electrochemical reaction. In addition, it can avoid CoSnO3@ZnSnO3 agglomeration and further improve storage capacity and stability. When the current density is 0.5 A g−1, the capacitance of material is 400.2 F g−1, which is higher than CoSnO3 and CoSnO3@ZnSnO3. Besides, the capacity retention rate of CoSnO3@ZnSnO3/rGO reaches 85% after 1100 cycles at a current density of 3 A g−1. This work demonstrates the interaction between the modification of the rGO network and the multi-layered hollow structure with the high specific surface areas can provide large spaces to effectively buffer volume changes and facilitate electron and electrolyte ion transport.

An Assay of Electrodeposited Cobalt Oxide Thin Film as a Supercapacitor Electrode

AbstractThe present research work is a humble effort to synthesize cobalt oxide supercapacitive electrode by electrodeposition method via potentiostatic mode of thin film deposition. The cobalt hydroxide material is deposited on stainless steel substrate at room temperature and annealed at 500°C to form cobalt oxide thin film electrode. The structural, morphological, and wettability investigation of the as‐deposited cobalt oxide thin film electrode is done by XRD‐analysis, SEM characterization, and contact angle measurement, respectively. The supercapacitive properties are investigated in aqueous 1M Na2SO4 electrolyte by cyclic voltametry and galvanostatic charge–discharge analysis. The results of the investigations are maximum specific capacitance of 284.4 F g−1 at a scan rate 5 mV s−1, specific energy 4.325 Wh kg−1, specific power 3 kW kg−1, and Coulomb efficiency 53.75%. The results so obtained promote cobalt oxide to be a challenging material for energy storage devices and supercapacitor applications.

CoCu2O4 nanoflowers architecture as an electrode material for battery type supercapacitor with improved electrochemical performance

In this study, an efficient electroactive material of CoCu2O4 with nanoflowers-like architecture has been developed by simplistic and low-cost hydrothermal technique without binders. The CoCu2O4 nanoflowers architecture provides large surface area and boosts the rating of ion accessibility and the speed of electrons transfer and thus enhances the electrochemical activities. In aqueous electrolyte, the present CoCu2O4 nanoflowers electrode exhibited a high specific capacity of 354.12 C g−1 at 2 A g−1. After 3000 long and continuous charging/discharging cycles, 97.3% of the initialing capacity has was retained. This super-active electrochemical properties of the CoCu2O4 nanoflowers architecture are mainly attributed to the enhanced surface area and to the improved ion transportation, which make it a promising candidate as an electrode material for energy storage supercapacitors.

Integrated standalone hybrid solar PV, fuel cell and diesel generator power system for battery or supercapacitor storage systems in Khorfakkan, United Arab Emirates

Renewable energy resources play a very important rule these days to assist the conventional energy systems for doing its function in the UAE due to high greenhouse gas (GHG) emissions and energy demand. In this paper, the analysis and performance of integrated standalone hybrid solar PV, fuel cell and diesel generator power system with battery energy storage system (BESS) or supercapacitor energy storage system (SCESS) in Khorfakkan city, Sharjah were presented. HOMER Pro software was used to model and simulate the hybrid energy system (HES) based on the daily energy consumption for Khorfakkan city. The simulation results show that using SCESS as an energy storage system will help the performance of HES based on the Levelized cost of energy (LCOE) and greenhouse gas (GHG) emissions. The HES with SCESS has renewable fraction (68.1%) and 0.346 $/kWh LCOE. The HES meets the annual AC primary load of the city (13.6 GWh) with negligible electricity excess and with an unmet electrical load of 1.38%. The reduction in GHG emissions for HES with SCESS was 83.2%, equivalent to saving 814,428 gallons of diesel.

Metal-organic framework composites for energy conversion and storage

Metal-organic frameworks (MOFs) with orderly porous structure, large surface area, high electrochemical response and chemical tunability have been widely studied for energy conversion and storage. However, most reported MOFs still suffer from poor stability, insufficient conductivity, and low utilization of active sites. One strategy to circumvent these issues is to optimize MOFs via designing composites. Here, the design principle from the viewpoint of the intrinsic relationships among various components will be illuminated to acquire the synergistic effects, including two working modes: (1) MOFs with assistant components, (2) MOFs with other function components. This review introduces recent research progress of MOF-based composites with their typical applications in energy conversion (catalysis) and storage (supercapacitor and ion battery). Finally, the challenges and future prospects of MOF-based composites will be discussed in terms of maximizing composite properties.

Bimetallic MnCo alloy nanoparticles decorated boron-doped carbon nanotubes as an active and durable electrode for supercapacitor

Abstract The demand for low-cost and high-performance energy storage supercapacitors is continuously promoting as a result of the rapid development of portable electric vehicles and electronic devices. Here, a high-performance MnCo alloy nanoparticles decorated boron-doped carbon nanotubes (MnCo–B/CNTs) electrode was obtained by a facile heteroatom hydrothermal and subsequent liquid-phase reduction methods, which yields improved performance for supercapacitor. In this process, boron doping led to extra oxygen graft into carbon surface, leading to the improved durability and wettability of the fabricated carbon-based electrodes, which presented both increased capacitances and rate capability due to electrolyte ion penetration and interactions with carbon surface. In addition, boron doping led to smaller size and higher dispersion of MnCo nanoparticles, facilitating more metallic alloy and new electroactive sites formation and promoting supercapacitive activity, which was attributed to increased MnCo alloy nucleation rate with boron-doped, electron donation from boron to alloy, and extra chemisorption sites. The constructed electrode exhibited all-round performance improvements of specific capacitance (1175 F g−1 at 0.5 A g−1) and capacitance retention (94.48% at a current density of 20 A g−1 after 5000 cycles), providing a novel insight for designing high performance supercapacitors.

Investigation of electrochemical performance of a new nanocomposite: CuCo2S4/Polyaniline on carbon cloth

Abstract A new nanocomposite based on CuCo2S4 nanosheets and polyaniline conducting polymer is synthesized and introduced as an electrode material for energy storage supercapacitors. First, CuCo2S4 nanosheets are prepared on carbon cloth through hydrothermal route and a wide potential window of 1.2 V is obtained for this material in Na2SO4 electrolyte. Then, a nanocomposite with an optimized amount of polyaniline is synthesized through chemical polymerization of aniline monomer on the surface of CuCo2S4 nanosheets and its electrochemical behavior is studied. Regarding the synergistic effect between polyaniline and CuCo2S4, the resultant CuCo2S4/polyaniline electrode exhibits a wider potential range and an improved specific capacitance of 920 F g−1 at a current density of 1 A g−1, significantly higher compared to that of bare CuCo2S4 nanosheets (780 F g−1). Symmetric supercapacitor assembled by newly prepared CuCo2S4/polyaniline as both anode and cathode, demonstrated extended operating potential window (1.8 V) and delivered high energy density of 32.5 Wh kg−1 and power density of 900 W kg−1. These results confirm that the as-prepared nanocomposite exhibits improved electrochemical performance and is a promising candidate to be used in energy storage devices.

Autonomous Active Tag Using Energy Harvesting Strategies

In this work, we present autonomous active tags. The power sources of these active tags employ energy harvesting techniques, specifically, solar and mechanical techniques. The integration of these techniques, and the storage of the energy obtained with a supercapacitor, converts the active tag into an autonomous device. These tags work in a low power mode in which they dynamically adjust their radio communication capabilities. Such a configuration depends on the application. We tested the tags in a real environment with testing parameters to check the modules, meaning more wake-ups over a longer time. Under these conditions, the tags gather enough energy to autonomously maintain standby operation on a sunny day for ten hours. In conclusion, this autonomous active tag is a demonstration that the integration of energy harvesting techniques, supercapacitor storage and the management of low power modes for transceivers, microcontrollers, and memories creates a device without energy dependencies that only depends on the requirements, and can be used in many applications related to, for instance, smart homes, smart cities, smart cars, and connected forests.