Fig 1 - uploaded by Laurent Pilon
Content may be subject to copyright.
Schematic of one-dimensional hybrid supercapacitor consisting of a pseudocapacitive electrode and a carbon electrode with LiClO4 electrolyte in PC. The dotted line encloses the computational domain considered.
Source publication
This study aims to provide metrics and design rules for hybrid pseudocapacitors consisting of a transition metal oxide pseudocapacitive electrode and an inert carbon electrode with asymmetric and binary electrolyte. Hybrid pseudocapacitors are often limited by intercalation of Li+ ions in the pseudocapacitive electrode. Then, during cyclic voltamme...
Context in source publication
Context 1
... do so, dimensional analysis of the continuum model recently developed -to simulate hybrid pseudocapacitors subjected to cyclic voltammetry [22] -was performed to capture the combined effects of electrode thickness, diffusion coefficient for intercalation, and scan rate. Figure 1 shows the schematic of the one-dimensional (1D) hybrid pseudocapacitor simulated as well as the computational domain and the associated coordinate system. The origin was located at the midplane of the cell. ...
Citations
... In comparison to other cathode materials, the electric conductivity of To begin our study, we first estimate the magnitudes of Wa and µ. The exchange current i 0 is estimated to be i 0 = 10 A/m 2 based on the expression provided by Girard et al. [47]. In reality, it is possible that the exchange current i 0 may depend on temperature, and this would affect the resulting dimensionless groups. ...
Rechargeable batteries that incorporate shaped three-dimensional electrodes have been shown to have increased power and energy densities for a given footprint area when compared to a conventional geometry, i.e., a planar cathode and anode that sandwich an electrolyte. Electrodes can be shaped to enable a higher loading of active material, while keeping the ion transport distance small, however, the relationship between electrical and mechanical performance remains poorly understood. A variety of electrode shapes have been explored, where the electrodes are individually shaped or intertwined with one another. Advances in manufacturing and shape and topology optimization have made such designs a reality. In this paper, we explore sinusoidal half cells and interdigitated full cells. First, we use a simple electrostatics model to understand the cell resistance as a function of shape. We focus on low-temperature conditions, where the electrolyte conductivity decreases and the governing dimensionless parameters change. Next, we use a chemo-mechanics model to examine the stress concentrations that arise due to intercalation-driven volume expansion. We show that shaped electrodes provide a significant reduction in resistance, however, they result in unfavorable stress concentrations. Overall, we find that the fully interdigitated electrodes may provide the best balance with respect to this trade-off.
... This material composition enables the electrodes to exploit the large surface area of the carbon-based material for electrostatic charge storage (similar to EDLC behavior), while also employing the redox properties of pseudocapacitive materials for faradaic charge storage (pseudocapacitance) [45], [C1]. ▪ Asymmetric hybrid supercapacitors utilize two different materials for each electrode, a carbon-based material for the negative electrode and a conducting polymer for the positive electrode [46]. This makes the Asymmetric electrode couple a half EDLC and half Pseudocapacitor [46]. ...
... ▪ Asymmetric hybrid supercapacitors utilize two different materials for each electrode, a carbon-based material for the negative electrode and a conducting polymer for the positive electrode [46]. This makes the Asymmetric electrode couple a half EDLC and half Pseudocapacitor [46]. The asymmetric design is often considered a solution to the high-energy versus power density tradeoff [47], [C1]. ...
Photovoltaic (PV) panels are the most used renewable source in both industrial and residential applications. Renewable sources such as solar and wind are intermittent, fluctuating power output, and it does not necessarily meet the consumption profile. Solving the intermittency issue comes by using energy storage (ES) for the generated electrical energy coming from the PV panels. Integrating ES directly into the PV panel offers benefits such as simplified system design and enhanced system flexibility. LiB is the most common and mature ES technology. Using Batteries as ES are known to have a shorter lifetime compared to solar panels and the power electronics lifetime, which makes the batteries the weakest link in the chain. Also using LiBs in outdoor conditions accelerates its degradation. For such outdoor applications requiring ES, supercapacitors emerge as a solution for making ES with a much longer cycling life, higher power density, and better safety when compared to LiB. While LiB is much affected by lower temperatures as the capacity drops and equivalent series resistance (ESR) increase and in higher temperatures the degradation of the LiB is accelerated, supercapacitors appear to be more tolerant to climatic variables. Supercapacitors such as Electrostatic double-layer capacitors (EDLCs) store energy in the form of an electric field, which is not dependent on chemical properties, or temperature and less suffering from material degradation. Using graphene-based electrodes EDLCs appear very promising but still lag the LiB in terms of energy density. On the other hand, Hybrid supercapacitors are halfway between EDLCs and LiBs and were developed to combine the advantages of EDLC such as temperature stability, high-power density, higher life cycles, and the advantages of LiBs such as higher energy density. Hybrid supercapacitors differ from EDLCs in being asymmetric, they use a carbon-based material only for the negative electrode and a battery electrode on the positive side. The selected Hybrid supercapacitor cells for this work were commercially available, high-energy density Li-ion capacitor (LiC) cells. Characterization tests were performed on the LiC by testing its parameters in different temperature conditions and charging/discharging currents. Extensive laboratory characterization test results are used to model the behavior of the LiC in the outdoor situation as ES for PV systems. Using ES outdoors exposes the cells to variable temperatures, which affect the performance (i.e., capacity, power capability etc.) of the ES. The integrated ES of the PV system is exposed to the temperature variations outdoors and sized for the case of LiC ES and LiB ES. As the LiB capacity drops in the lower temperatures, LiB is oversized to overcome this capacity drop. LiC’s capacity is less affected by temperature, thus the LiC is not oversized compared to the LiB. Defining the optimal ES size is not only dependent on the current capacity of the storage cells but also on the capacity of the cells after a number of cycles and considering the effect of the operating in environmental conditions on aging. For this reason, aging tests were required to develop such an aging model for the LiC. A 3x3 test matrix with two axes representing temperature and current was used for cycling five LiC test cells in different conditions; extrapolation was considered to determine the capacity and ESR of the LiCs for the untested conditions. Green Hydrogen production is an alternative method of storing the energy produced from PV panels. Also, Green Hydrogen is an alternative to natural gas and can be used in applications such as heating and transportation. Green hydrogen is produced in a process called electrolysis using a Proton Exchange Membrane (PEM) electrolyzer. But even in the application of green hydrogen production, an electric ES is required to keep the PEM electrolyzer in the production mode even after sunset or in idle mode to avoid complete shutdown and restart, which reduces the lifetime of the electrolyzer. To manage the green hydrogen production from PV throughout the day and from ES at night, a basic energy management system (EMS) is used. The ES is optimized for different scenarios using LiC and LiB. A sensitivity analysis of LiC and LiB ES is performed for the PV green hydrogen production system considering local irradiance and temperature conditions in the Australian climate. The study considers tradeoff scenarios between ES size and hydrogen production, suggests the best ES technology for PV green hydrogen production in Australia, and the suggests an energy management strategy for this application.
... If a material with a high specific surface area is used as the electrode, more electrochemical reactions could occur, and more charge could be stored during the charging process. The electrolyte ions adsorbed on the electrodes will return to the electrolyte by chemical desorption in the discharge process, thus exhibiting capacitance characteristics, and therefore the pseudocapacitors designation [11][12][13]. Since the pseudocapacitor involves the transfer of charges, its charge storage is much larger than that of the traditional capacitor and the EDLC. ...
The energy demand has grown explosively due to the changes in the world economy and the rapid development of society. Improving energy utilization and energy storage has thus become an essential area of science and technology development. Supercapacitors are necessary energy-storage devices, and their growth has become the goal of significant national efforts. We prepared a sandpaper-based composite electrode by mixing multiwalled carbon nanotubes (MWCNTs) and graphene with a conductive polymer, poly(3,4-ethylenedioxythiophene) (PEDOT), with pseudocapacitance characteristics. The specific capacitance of the composite electrode was effectively increased from 55 to 124 F/g by 3% PEDOT addition. Furthermore, the internal resistance of the electrolyte was effectively reduced, and the electrode capacitance increased to 137 F/g by adding 1.0% MWCNTs to the phosphate gel electrolyte. The specific capacitance of the energy-storage device still retained 97% of its initial value after the charge–discharge cycle testing under constant current, which is an excellent cycling-life performance. The hybrid supercapacitor in this study has considerable development potential in flexible wearable devices and energy-storage component fields.
Graphical Abstract
... To assess and optimise the weight ratio of GNRs: CoFe 2 O 4 , cyclic voltammetry studies were carried out. The presence of a redox peak in the CV investigation was a result of the faradaic charge transfer and pseudocapacitative properties of the CoFe 2 O 4 /GNRs [46]. Although the excessive amount of GNRs, which was investigated at a weight ratio of 1:5 and 1:8, resulted in agglomeration, with the increasing amount of GNRs, the capacitance improved and the reduction of capacitive loss abilities may be due to the empty spaces between nanoparticles that were not relatively filled by GNRs as the supporting material for CoFe 2 O 4 nano-particles [46]. ...
... The presence of a redox peak in the CV investigation was a result of the faradaic charge transfer and pseudocapacitative properties of the CoFe 2 O 4 /GNRs [46]. Although the excessive amount of GNRs, which was investigated at a weight ratio of 1:5 and 1:8, resulted in agglomeration, with the increasing amount of GNRs, the capacitance improved and the reduction of capacitive loss abilities may be due to the empty spaces between nanoparticles that were not relatively filled by GNRs as the supporting material for CoFe 2 O 4 nano-particles [46]. Nanoribbons, as excellent substrates with high electrical conductivity and electron transference into nanoparticles, as well as conspicuous electrochemical activity, contribute significantly to the specific capacitance of nanomaterial. ...
CoFe2O4/Graphene Nanoribbons (GNRs) nanocomposite was successfully fabricated and utilised as an electrode active material for high-energy supercapacitor cells. Thanks to the outstanding physicochemical features of a graphene nanoribbon with excellent electrical conductivity and the synergistic effect with cobalt ferrite, as well as the pseudocapacitive effect. The CoFe2O4/GNRs nanohybrid offered an exceptional specific capacitance of 922 F g−1 (415 C g−1) at 1.0 A g−1 in 3.0 M KOH electrolyte in a standard 3-electrode set-up. Additionally, the impressive supercapacitive performance metrics showed that the suggested electrode had a distinctive morphology and could be a candidate for capacitive energy storage systems. These metrics included good cycle stability and 87% capacitance retention at the end of the 10,000th CV cycle. Moreover, the asymmetric supercapacitor cell (ASC) was designed by assembling CoFe2O4/GNRs and activated carbon (AC). The resultant ASC provided an improved specific capacitance of 487.85 F g−1 (683 C g−1) at 1.0 A g−1. At this current density value, the energy density and the power density values were computed as to be 132.8 Wh.kg−1 and 632.39 W kg−1. The highest power density was discovered to be 6730.76 W kg−1 at 10.0 A g−1, whereas the energy density was determined as 8.75 Wh.kg−1 at this current density. The results of the work proved that CoFe2O4/GNRs nanohybrids are up-and-coming electrode active materials for advanced electrochemical energy storage and conversion technologies.
... The capacitive current increases as the scan rate increases and the shape of the CV plots gradually changes from rectangular to oval, due to the internal resistance of the electrode. Which may be due to the limited charge accumulation and low conductivity of Li 2 SO 4 aqueous solution, as well as the diffusion limits of Li + and SO 4 − 2 ions in the electrodes [56,57]. As the voltage scan rate increased, the deviation of the voltammogram from the ideal rectangular structure also increased. ...
Ruthenium antimony oxide (RuSbO), and ruthenium antimony oxide graphene (RuSbO-G) nanomaterial was synthesized via the microwave-assisted method for the first time and tested as a possible electrode material for an asymmetric supercapacitor device. The formation of the nanocomposites was confirmed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images where the RuSbO material showed randomly distributed spherically shaped nanoparticles, and the RuSbO-G showed ruthenium and antimony nanoparticles scattered randomly on the graphene sheets. The SEM-electron dispersion X-ray spectroscopy (SEM-EDS) showed significant proof for nanoparticle formation with the elemental composition, while the X-ray photoelectron spectroscopy confirmed the oxidation states of the elements present. Both materials were further characterized in a three-electrode cell setup using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) and electrochemical impedance spectroscopy (EIS) and their electrochemical properties were compared to establish their suitability for energy storage purposes. From the result, different double layer properties were shown by the RuSbO and RuSbO-G in the 1 M Li2SO4 electrolyte. When compared to the RuSbO electrode, the composite had greater energy storage capabilities with a maximum capacitance of 289.47 F g−1 at 0.1 A g−1 current load. An efficiency of ~100 % was reached at a current density of 0.5 A g−1. Subsequently, both materials were used to fabricate a portable asymmetric supercapacitor. The RuSbO-G device yielded a maximum specific capacitance of 167.96 F g−1, resulting in an energy density of 75.58.0 W h kg−1 at a power density of 360 W kg−1 at 0.1 A g−1 current load, with ~100 % charge retention after 4900 cycles. This study turns a new research light on RuSbO based materials as an energy storage material for supercapacitors.
... In this configuration, the battery is dir nected to the DC link, while the SC is connected to the DC link through a DC-to verter. Since the battery is directly connected to the DC link, it can maintain th voltage, while SCs can be operated to deal with large current fluctuations [34] proach is typically preferred when a smaller SC pack is used due to its cost-effe and compactness [34]. Moreover, with the direct connection of the battery to the it is possible to have situations where large currents may be drawn from the b stead of the SC due to the converter delays [35]. ...
... In this configuration, the battery is dir nected to the DC link, while the SC is connected to the DC link through a DC-to verter. Since the battery is directly connected to the DC link, it can maintain th voltage, while SCs can be operated to deal with large current fluctuations [34] proach is typically preferred when a smaller SC pack is used due to its cost-effe and compactness [34]. Moreover, with the direct connection of the battery to the it is possible to have situations where large currents may be drawn from the b stead of the SC due to the converter delays [35]. ...
... In this configuration, the battery is directly connected to the DC link, while the SC is connected to the DC link through a DC-to-DC converter. Since the battery is directly connected to the DC link, it can maintain the DC link voltage, while SCs can be operated to deal with large current fluctuations [34]. This approach is typically preferred when a smaller SC pack is used due to its cost-effectiveness and compactness [34]. ...
Supercapacitors can store a million times more energy per unit mass or volume compared to electrolytic capacitors. Due to their low internal resistance, they are capable of driving or absorbing pulsative high currents. Over the last quarter, century supercapacitor (SC) manufacturers have developed several families of mass-scale devices with high-power density and a longer cycle life that helped the end-users to improve their energy storage systems and products. Today, there are three common device families, namely, (i) symmetrical double-layer capacitors (EDLCs), (ii) hybrid capacitors with a lithium electrode, and (iii) battery capacitors based on pseudo capacitance concepts. This review paper compares these families and provides an overview of several state-of-the-art applications in electric vehicles (EVs), microgrids, and consumer electronics.
... Hybrid supercapacitors are asymmetric supercapacitors [6] that use a carbon-based material only for the negative electrode, while the positive is a battery electrode [7]. A comparison between the lithium-ion battery and hybrid supercapacitor in the application of off-grid PV systems was performed in [8]. ...
... 24 Lin's first model combining pseudocapacitive and double layer processes in a porous metal oxide supercapacitor structure has provided the basis for many further models of metal oxide supercapacitor systems. 25 The Lin model has been expanded on by application to oxide/carbon composite systems with proton diffusion effects; 26,27 describing the behavior of asymmetrical supercapacitors; [28][29][30] describing hybrid battery/supercapacitor systems; [31][32][33] use with other metal oxides; 34-36 examining varying geometries including nanorods, 37 interdigitated electrodes, 38 and changes in electrode thickness and porosity; 39 and to account for self-discharge and side reactions. 40,41 Other models integrate more complex descriptions of double layer capacitance to more accurately account for ion interactions in the electrolyte and with the electrode surface 42 or describe moving reaction fronts through the electrode thickness. ...
Supercapacitors are an important energy storage technology that combine the high energy density of batteries with the high power density of capacitors. Freestanding Mn2O3 electrodes fabricated via electrospinning and calcination have the potential to provide high power and energy densities with low fabrication costs. In this work, a theoretical model is produced to describe the effects of the electrospun structure on electrode performance. The model uses theoretical predictions of capacitive and faradaic energy storage, based on system parameters measured from real electrodes to produce a realistic model that can be used for engineering design and optimization of the electrodes. Porosity-controlled discharge time and extremely stable energy densities are predicted by the model. Results are compared to discharge curves of a real electrode to examine model fidelity.
... On the other hand, the carbon-based electrode has lower maximum voltages and less cycling stability than polymer-based electrodes. This Asymmetric electrode couple are half EDLC and half Pseudocapacitor [35]. Asymmetric Hybrid supercapacitor is the solution for the tradeoff between the high energy vs power density [36]. ...
One limitation of photovoltaic energy is the intermittent and fluctuating power output, which does not necessarily follow the consumption profile. Energy storage can mitigate this issue as the generated power can be stored and used at the needed time. Integrating energy storage directly in the PV panel provides advantages in terms of simplified system design, reduced overall cost and increased system flexibility. Incorporating supercapacitors directly in the PV panel on module or cell level raises some challenges regarding the electrical integration, such as charge controlling for the capacitors, capacitor matching, as well as internal power electronics layout. Physical integration of graphene supercapacitors with solar cells, at module- or cell-level presents challenges related to physical dimensioning, thermal management and life expectation of the entire system. The main goal of this article is to review the supercapacitor technologies and perform a comparison between the available supercapacitors in the market and selecting the most suitable type for developing supercapacitor-based integrated PV – energy storage systems, to achieve optimal electrical and physical integration.
... However for solvated ion diameter a = 1.40 nm, C s and C g came out to be 7.5μFcm −2 and 72 Fg −1 respectively which were about 24% lesser than their observed experimental values. 1D continuum transport model are also used to describe the hybrid pseudocapacitor based on the lithium intercalation and diffusion in metal oxide [38]. The objective was to design rules for pseudocapacitive electrodes ensuring that the hybrid pseudocapacitor operates exclusively in the faradaic regime. ...
Supercapacitors provide remarkable eco-friendly advancement in energy conversion and storage with a huge potential to control the future economy of the entire world. Currently, industries focus on the design and engineering aspects of supercapacitors with high performance (high energy), flexibility (by the use of composite polymer based electrolytes), high voltage (ionic liquid) and low cost. The paper reviews the modelling techniques like Empirical modelling, Dissipation transmission line models, Continuum models, Atomistic models, Quantum models, Simplified analytical models etc. proposed for the theoretical study of Supercapacitors and discusses their limitations in studying all the aspects of Supercapacitors. It also reviews the various software packages available for Supercapacitor (SC) modelling and discusses their advantages and disadvantages. The paper also reviews the Experimental advancements in the field of electric double layer capacitors (EDLCs), pseudo capacitors and hybrid/asymmetric supercapacitors and discusses the commercial progress of supercapacitors as well.
