Supercapacitor Storage Research Articles

Potential Applications of Nickel-Based Metal-Organic Frameworks and their Derivatives.

Metal-Organic Frameworks (MOFs), a novel class of porous extended crystalline structures, are favored in different fields of heterogeneous catalysis, CO2 separation and conversion, and energy storage (supercapacitors) due to their convenience of synthesis, structural tailor-ability, tunable pore size, high porosity, large specific surface area, devisable structures, and adjustable compositions. Nickel (Ni) is a ubiquitous element extensively applied in various fields of catalysis and energy storage due to its low cost, high abundance, thermal and chemical stability, and environmentally benign nature. Ni-based MOFs and their derivatives provide us with the opportunity to modify different properties of the Ni center to improve their potential as heterogeneous catalysts or energy storage materials. The recent achievements of Ni-MOFs and their derivatives as catalysts, membrane materials for CO2 separation and conversion, electrode materials and their respective performance have been discussed in this review.

Multi-Time scale control framework of hybrid energy storage system via robust control and virtual impedance

Aiming at the problems of the strong randomness and fluctuation of the output power in photovoltaic power generation system, a multi-time scale control framework of hybrid energy storage system is proposed. Firstly, the complementary characteristics of charge/discharge between lithium battery and supercapacitor is analyzed. Then, The models of lithium battery energy storage unit and supercapacitor energy storage unit are established, respectively. Considering the different time scales of the output power response of lithium battery and supercapacitor, a short-time scale control framework is designed for supercapacitor energy storage unit based on the robust control, so that the bus voltage of system can be stable when the output power of photovoltaic power generation system changes or the load changes rapidly. At the same time, a long-time scale control framework is designed for lithium battery energy storage unit based on the virtual impedance, so that the voltage of the supercapacitor can be maintained within set value when the output power of the photovoltaic power generation system is stable. Therefore, the multi-time scale control framework can not only realize the large current charging/discharging for lithium battery and the power tracking at low frequency, but also realize the small current charging/discharging for supercapacitor and the power tracking at high frequency. Finally, the effectiveness of the proposed framework is verified by the simulation platform of photovoltaic power generation system.

A bright future of hydrogels in flexible batteries and Supercapacitors storage systems: A review

A bright future of hydrogels in flexible batteries and Supercapacitors storage systems: A review

Enhanced electrochemical performance of vanadium carbide MXene composites for supercapacitors

Two-dimensional (2D) surface-terminated layered transition metal carbide MXenes with high electrochemical performance paved the way for robust energy storage supercapacitor devices. However, because of the 2D nature of the MXene flakes, self-restacking of 2D MXene flakes limits the use of all the flake functionalized surfaces in MXene electrodes. Here, we report the synthesis of V2CTx MXene and multiwall carbon nanotube (MWCNT)/V2CTx composites as a promising electrode material for hybrid energy storage devices. Our hybrid electrodes exhibited enhanced electrochemical performance and a gravimetric capacitance of 1842 F g−1 at a scan rate of 2 mV s−1, with a specific charge capacity of 62.5 A h/g. Moreover, the electrodes presented an excellent rate performance, durability, and retention capacity of 94% lasted up to 10 000 cycles. Density functional theory calculations provided electronic and structural properties of the considered MWCNT@V2CTx. Therefore, the introduction of MWCNTs enhanced the conductivity and reaction kinetics of the MXenes and facilitates the charge storage mechanism useful for next-generation smart energy storage devices.

Cellulose Nanocrystals (CNC)-Based Functional Materials for Supercapacitor Applications

The growth of industrialization and the population has increased the usage of fossil fuels, resulting in the emission of large amounts of CO2. This serious environmental issue can be abated by using sustainable and environmentally friendly materials with promising novel and superior performance as an alternative to petroleum-based plastics. Emerging nanomaterials derived from abundant natural resources have received considerable attention as candidates to replace petroleum-based synthetic polymers. As renewable materials from biomass, cellulose nanocrystals (CNCs) nanomaterials exhibit unique physicochemical properties, low cost, biocompatibility and biodegradability. Among a plethora of applications, CNCs have become proven nanomaterials for energy applications encompassing energy storage devices and supercapacitors. This review highlights the recent research contribution on novel CNC-conductive materials and CNCs-based nanocomposites, focusing on their synthesis, surface functionalization and potential applications as supercapacitors (SCs). The synthesis of CNCs encompasses various pretreatment steps including acid hydrolysis, mechanical exfoliation and enzymatic and combination processes from renewable carbon sources. For the widespread applications of CNCs, their derivatives such as carboxylated CNCs, aldehyde-CNCs, hydride-CNCs and sulfonated CNC-based materials are more pertinent. The potential applications of CNCs-conductive hybrid composites as SCs, critical technical issues and the future feasibility of this endeavor are highlighted. Discussion is also extended to the transformation of renewable and low-attractive CNCs to conductive nanocomposites using green approaches. This review also addresses the key scientific achievements and industrial uses of nanoscale materials and composites for energy conversion and storage applications.

Design of Ni(OH)2/M-MMT Nanocomposite With Higher Charge Transport as a High Capacity Supercapacitor.

Nano-petal nickel hydroxide was prepared on multilayered modified montmorillonite (M-MMT) using one-step hydrothermal method for the first time. This nano-petal multilayered nanostructure dominated the ion diffusion path to be shorted and the higher charge transport ability, which caused the higher specific capacitance. The results showed that in the three-electrode system, the specific capacitance of the nanocomposite with 4% M-MMT reached 1068 F/g at 1 A/g and the capacity retention rate was 70.2% after 1,000 cycles at 10 A/g, which was much higher than that of pure Ni(OH)2 (824 F/g at 1 A/g), indicating that the Ni(OH)2/M-MMT nanocomposite would be a new type of environmentally friendly energy storage supercapacitor.

Power Supply Based on Inductive Harvesting From Structural Currents

Monitoring infrastructure offers functional optimization, lower maintenance cost, security, stability, and data analysis benefits. Sensor nodes require some level of energy autonomy for reliable and cost-effective operation, and energy-harvesting methods have been developed in the last two decades for this purpose. Here, a power supply that collects, stores, and delivers regulated power from the stray magnetic field of current-carrying structures is presented. In cm-scale structures the skin effect concentrates current at edges at frequencies even below 1 kHz. A coil-core inductive transducer is designed. A flux-funneling soft magnetic core shape is used, multiplying power density by the square of funneling ratio. A power management circuit combining reactance cancelation, voltage doubling, rectification, supercapacitor storage, and switched inductor voltage boosting and regulation is introduced. The power supply is characterized in house and on a full-size industrial setup, demonstrating a power reception density of 0.36, 0.54, and 0.73 mW/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> from a 25-A root-mean-square structural current at 360, 500, and 800 Hz, respectively, corresponding to the frequency range of aircraft currents. The regulated output is tested under various loads and cold starting is demonstrated. The introduced method may enable power autonomy to wireless sensors deployed in current-carrying infrastructure.

Flexible carbon nanofiber yarn electrodes for self-standing fiber supercapacitors

In this study, polyacrylonitrile (PAN) nanofiber yarns were obtained by twisting the nanofiber mat strips produced in the electrospinning device. On the drum collector, the nanofibers are produced in such a way that the diameter change can be controlled. Through stabilization and carbonization processes, PAN nanofiber yarns were converted to carbon nanofiber (CNF) yarns. The stabilization process stabilized the yarn structure, which was previously unstable, due to thermal treatments. The obtained CNF yarn had a diameter of approximately 360 μm and an average nanofiber diameter of 123 ± 20 nm. On a three-electrode system, the electrochemical performance of CNF yarn in 1 m H2SO4 electrolyte was determined using cyclic voltammetry and galvanostatic charge/discharge test methods. The specific capacitance of the CNF yarn electrode was determined to be 145 F/g at a current density of 0.2 A/g. Up to 500 charge/discharge cycles, the specific capacitance increased by approximately 20% and remained constant thereafter. Due to their superior properties such as high surface area, lightweight, and flexibility, CNF yarn electrodes can be used in a wide variety of electronic applications, including energy harvesting, energy storage (supercapacitors, batteries, etc.), and sensors.

Influence of NiO and La2O3 nanoparticles on the optical, mechanical and electrical properties of PVAc–PMMA blend: a comparative study

Nano-sized metal oxides are fascinating materials as fillers used for improving the polymeric materials’ performance and expanding their multifunctionality. Two metal oxides; NiO and La2O3 nanoparticles (NP) were prepared and introduced into poly(vinyl acetate)/poly(methyl methacrylate), PVAc/PMMA blend via solution casting route. XRD and HR-TEM analysis confirmed the preparation of a cubic NiO and a hexagonal La2O3 NP with an average crystallite size of 59.85 and 29.13 nm, respectively. Introducing NiO and La2O3 increases the films’ amorphous structure. FTIR analysis confirmed the existence of all blend’ functional groups and hydrogen bond formation. SEM investigation showed that NiO or La2O3 loading affects the blend surface morphology. A UV–vis-NIR study showed that NiO narrowed the direct bandgap of the blend from 4.1 to 3.3 eV, whereas La2O3 reduced it to 3.4 eV. 1.0 wt% NiO significantly improved the various optical constants of the blend. DMA revealed that storage modulus G′ increased with loading of 1 wt% NiO or La2O3 by 79.3% and 51.0%, respectively while G′ decreased with heating. The dielectric behavior of films is analyzed using several dielectric parameters. The maximum σ ac reported for 1.0 wt% NiO/blend film is 5.8 × 10−6 (S/cm). The AC conduction mechanism is discussed for all films in the temperature and frequency ranges (298−373 K) and (5 Hz−2 MHz). 1.0 wt%/PVAc/PMMA nanocomposite showed enhanced optical and mechanical properties, making it suitable for architectural, flexible display screens, and photovoltaic cell devices. Moreover, loading NiO and La2O3 improved the dielectric properties of the blend to be used in the semiconductor industry, besides energy storage devices and supercapacitors.

Recent Progress in Carbonaceous and Redox-Active Nanoarchitectures for Hybrid Supercapacitors: Performance Evaluation, Challenges, and Future Prospects.

Due to advancements in technology, the energy demand is becoming more intense with time. The rapid fossil fuels consumption and environmental concerns triggered intensive research for alternative renewable energy resources, including sunlight and wind. Yet, due to their time-dependent operations, significant electric energy storage systems are required to store substantial energy. In this regard, electrochemical energy storage devices, like batteries and supercapacitors (SCs), have recently attracted much research attention. Recent developments in SCs demonstrated that hybrid SCs (HSCs), which combine the excellent properties of batteries and SCs, increase the specific energy, specific power, specific capacitance, and life span. Carbonaceous and redox-active materials have been explored as efficient electrode materials for applications in HSCs, ultimately enhancing their electrochemical performances. The HSCs performance significantly depends on the porosity, specific surface area, and conductivity of the electrode materials. This review article gives an overview of recent advances in developing HSCs with high specific power, specific energy, and long cyclic-life. The fabrication of various HSCs materials using carbonaceous and redox-active nanoarchitectures and their characterization are explored in-depth, including electrode development, basic principles, and device engineering. A proper investigation has been conducted regarding state-of-the-art materials as HSC electrodes. This review focuses on the most up-to-date, cutting-edge, electrode materials for HSCs and their performance. The possibilities for novel electrode materials and their impact on the HSCs performance for future energy storage are also discussed.

Preparations and Applications of MXene–Metal Composites: A Review

MXene, an advanced family of 2D ceramic material resembling graphene, has had a considerable impact on the field of research because of its unique physiochemical properties. MXene has been synthesized by the selective etching of MAX via different techniques. However, with the passage of time, due to the need for further progress and improvement in MXene materials, ideas have turned toward composite fabrication, which has aided boosting the MXene composites regarding their properties and applications in various areas. Many review papers are published on MXene and their composites with polymer, carbon nanotube, graphene, other carbon, metal oxides and sulfides, etc., except metal composite, and such papers discuss these composites thoroughly. In this review article, we illustrate and explain the development of MXene-based metal composites. Furthermore, we highlight the synthesis techniques utilized for the preparation of MXene composites with metal. We briefly discuss the enhancement of properties of the composites and a wide range of applications as an electrode substance for energy storage devices, electrochemical cells, supercapacitors, and catalytic and anti-corrosive performance. Major obstacles in MXene and metal composite are mentioned and provide future recommendations. Together, they can overcome problems and enable MXene and composites on commercial-scale production.

One-step architecture of bifunctional petal-like oxygen-deficient NiAl-LDHs nanosheets for high-performance hybrid supercapacitors and urea oxidation

Nickel-based layered double hydroxides (LDHs) are promising electrode materials in the fields of energy storage (supercapacitors) and conversion (urea oxidation). The rational construction of atomic and electronic structure is crucial for nickel-based LDHs to realize their satisfactory electrochemical performance. Herein, we report a facile, ecofriendly, one-step synthesis process to construct petal-like oxygen-deficient NiAl-LDH nanosheets for hybrid super-capacitors (HSCs) and urea oxidation reaction (UOR). The asprepared NiAl−LDH nanosheets with rich oxygen vacancies possess a large specific surface area of 216.6 m2 g−1 and a desirable electronic conductivity of 3.45 × 10−4 S cm−1 to deliver an ultra-high specific capacitance of 2801 F g−1 (700 C g−1) at 1 A g−1. Furthermore, high specific energy of 50.0 W h kg−1 at 400 W kg−1 and excellent cycle stability with 91% capacitance retention after 10,000 cycles are achieved by the NiAl-LDHs/CFP (carbon fiber paper) (+)//YP-80F (a commercial activated carbon) (−) HSC. Besides, NiAl−LDH nanosheets also work as an efficient electrocatalyst for UOR, which only requires 1.42 V vs. reversible hydrogen electrode to drive 10 mA cm−2 in 1 mol L−1 KOH with 0.33 mol L−1 urea. This remarkable performance is superior to most reported values of previous candidates owing to the thin structure of NiAl−LDH nanosheets for exposing more active sites and abundant oxygen vacancies. In addition, various reaction parameters are investigated to optimize the electrochemical performance. In general, this work paves a new way for the architecture of multifunctional nanostructured energy materials.

Model predictive control of solar photovoltaic‐based microgrid with composite energy storage

SummaryThe renewable energy (e.g., solar photovoltaic)‐based grid‐connected microgrid (MG) with composite energy storage system (CESS) is feasible to ensure sustainable and quality power to the commercial and domestic load demands. Effective control systems provide the dynamic performance of such deployed MGs. This paper investigates the application of the finite control‐set model predictive controller (FCS‐MPC) for solar photovoltaic‐based grid‐connected MGs with composite energy storage. FCS‐MPC considers the discrete nature of interfacing (DC–AC and DC–DC) converters into the control algorithm to predict the optimal control command for reference current tracking. Compared to classical control approaches, FCS‐MPC provides a fast‐dynamic response, discards the modulation stage, and effectively handles the effects of dynamic source and load variations and nonlinear loads. The control system encapsulates a proportional–integral (PI) controller, low‐pass filter (LPF), power management algorithm (PMA) unit, and followed by the FCS‐MPC approach. The CESS unit consists of a battery and supercapacitor storage system. The efficacy of the FCS‐MPC approach is verified through the MATLAB/Simulink results. Solar photovoltaic variation due to irradiance, utility grid availability, electricity pricing, and dynamic load variations are considered in the implementation. Furthermore, real‐time simulation of the proposed method is validated using OPAL‐RT OP4510 real‐time simulator.

A nonlinear double‐integral sliding mode controller design for hybrid energy storage systems and solar photovoltaic units to enhance the power management in DC microgrids

In this paper, a nonlinear decentralized double-integral sliding mode controller (DI-SMC) is designed along with an energy management system (EMS) for the DC microgrid (DCMG). This DCMG includes having a hybrid energy storage system (HESS) that incorporates a battery energy storage system (BESS) and supercapacitor energy storage system (SCESS) while the load demand is met through the power generated from solar photovoltaic (SPV) units. First, dynamical models of each subsystem of DCMGs such as the SPV system, BESS, and SCESS are developed to capture highly nonlinear behaviors of DCMGs under various operating conditions. The proposed nonlinear DI-SMC is then designed for each power unit in DCMGs to ensure the desired voltage level at the common DC-bus and appropriate power dispatch of different components to fulfill the load requirement of the DCMG. On the other hand, an energy management system (EMS) is designed to determine the set point for the controller with an aim of ensuring the power balance within DCMGs under various operating conditions where the overall stability is assessed using the Lyapunov theory. Simulation studies along with the processor-in-loop validation, including a comparative study with a proportional-integral (PI) controller, verify the applicability and effectiveness of the EMS-based DI-SMC under different operating conditions of the DCMG.

Optimization of supercapacitor’s location and capacity in the urban railway lines based on greedy principle

Using energy storage equipment is an effective solution to improve energy efficiency for urban railway lines. Two of the important parameters are the location and capacity of the storage device that will determine the efficiency of the power supply system. This paper presents an algorithm that combines the greed principle and the retrieval principle to determine the optimal location and capacity of supercapacitor storage stations along the track to maximize the economic benefits. The proposed algorithm is tested on a simulation model built based on the data of the Cat Linh - Ha Dong urban railway line. The simulation results show that the optimal installation of energy storage stations will increase maximum energy efficiency to contribute to economic growth and reduce the load peaks that will be reducing voltage fluctuations.

Recent Advances in Boron‐ and Nitrogen‐Doped Carbon‐Based Materials and Their Various Applications

AbstractCarbon, owing to its unique properties such as surface area, pore features, conductivity, and chemical and thermal stability, has found several applications in the field of sensors, energy storage, electrocatalysis, and hydrogen storage. However, the properties of pristine carbon are sometimes insufficient to meet the requirements of a particular application. Heteroatom co‐doping may not only enhance the surface area, improve the porosity, and enhance the redox activity, but it also increases stability. B, N heteroatom co‐doping has gained popularity as it is found to be an effective way to enhance the properties of porous carbon by influencing the physicochemical, electrochemical, and electrical properties, thereby widening its applications. In this review, the rational synthetic strategies that are used to produce B, N co‐doped carbon are described. Further, the charge conduction in such B, N co‐doped carbon‐based materials (including metal and metal‐free) is discussed in detail. Certain remarkable works representing the various applications of B, N co‐doped carbon in the area of electrocatalysis, energy storage (rechargeable batteries and supercapacitors), and sensors are also highlighted. Finally, the review ends with a discussion of the existing challenges and possible future directions of research on B, N co‐doped carbon.

Novel g-C3N4/Cu-doped ZrO2 hybrid heterostructures for efficient photocatalytic Cr(VI) photoreduction and electrochemical energy storage applications

Pure ZrO2, graphitic carbon nitride, Cu-doped ZrO2 nanoparticles (Cu–Zr), and doped Cu–Zr nanoparticles decorated on the g-C3N4 surface (g-CuZr nanohybrids) were successfully prepared by a hydrothermal technique. Synthesized catalysts were examined by XRD, FE-SEM, TEM, UV–Vis spectroscopy, photoluminescence (PL), and BET surface measurements, respectively. The photocatalytic reduction of Cr(VI) photoreduction as well as energy storage supercapacitor applications were thoroughly investigated. The g-CuZr hybrid photocatalyst outperformed other pristine photocatalysts in terms of light absorption and catalytic Cr(VI) reduction performance under stimulated solar light irradiation. Furthermore, methylene blue (MB) was used as a photosensitizer to further improve the Cr(VI) photoreduction performance. In precise, the heterostructured hybrid catalyst exhibited improved photocatalytic Cr(VI) photoreduction activity (∼88.1%) in 5 mg/L MB solution over other catalysts. Moreover, the decoration of Cu–Zr on the surface of g-C3N4 enhanced the absorption ability of light and catalytic Cr(VI) photoreduction performance. The PL, EIS, and transient photocurrent analysis demonstrated that the efficiency of the charge carrier's separation in the nanohybrid catalyst was superior over other catalysts. Furthermore, heterostructured g-CuZr nanohybrid electrode exhibited superior specific capacitance (297.2 F/g) over other electrodes, which are 5.5 folds (54.01 F/g), ∼2 folds (144.01 F/g) better than pure ZrO2 and g-C3N4 electrodes. Likewise, the nanohybrid electrode retained about 90% of the capacitive value after 2500 cycles over its initial capacitance.

Vanadium‐based metal‐organic frameworks and their derivatives for electrochemical energy conversion and storage

AbstractWith the excessive consumption of nonrenewable resources, the exploration of effective and durable materials is highly sought after in the field of sustainable energy conversion and storage system. In this aspect, metal‐organic frameworks (MOFs) are a new class of crystalline porous organic‐inorganic hybrid materials. MOFs have recently been gaining traction in energy‐related fields. Owing to the coordination flexibility and multiple accessible oxidation states of vanadium ions or clusters, vanadium‐MOFs (V‐MOFs) possess unique structural characteristics and satisfactory electrochemical properties. Furthermore, V‐MOFs‐derived materials also exhibit superior electrical conductivity and stability when used as electrocatalysts and electrode materials. This review summarizes the research progress of V‐MOFs (inclusive of pristine V‐MOFs, V/M‐MOFs, and POV‐based MOFs) and their derivatives (vanadium oxides, carbon‐coated vanadium oxide, vanadium phosphate, vanadate, and other vanadium doped nanomaterials) in electrochemical energy conversion (water splitting, oxygen reduction reaction) and energy storage (supercapacitor, rechargeable battery). Future possibilities and challenges for V‐MOFs and their derivatives in terms of design and synthesis are discussed. Lastly, their applications in energy‐related fields are also highlighted.

Defective engineering of heterostructured N-Mo2C@MoO3-x electrode materials for the dual function of electrochemical sensing and supercapacitor applications

In this study, the novel nanostructure of N-Mo2C@MoO3-x hybrid electrode materials was successfully designed by the carbothermic process. N-Mo2C@MoO3-x hybrids were used for dual applications, such as non-enzymatic electrochemical detection of hydroquinone (HQ) and resorcinol (RS), and energy storage supercapacitor. In particular, the N-Mo2C@MoO3-x demonstrated a simultaneous detection of linear response to (HQ) and resorcinol (RS) in the concentration ranging from 0.04 to 400 μM and 0.1 to 350 μM. HQ and RS have detection limits of 0.005 and 0.01 μM (S/N = 3), respectively. In addition, the asymmetric supercapacitors (ASC) have been fabricated via a positive electrode of N-Mo2C@MoO3-x hybrids and a negative electrode of (RGO) nanosheets using a 1 M Na2SO4 electrolyte solution. The ASC has shown excellent electrochemical properties, such as high areal capacitance (0.8 F/cm2 at 0.1 A/g), cyclic stability (89.5% after 5000 cycles), energy density (224 and 140.8 Wh/kg) at a power density (20,160 and 33,600 W/kg), and excellent rate capability.

Janus 2D materials via asymmetric molecular functionalization.

Janus two-dimensional materials (2DMs) are a novel class of 2DMs in which the two faces of the material are either asymmetrically functionalized or are exposed to a different local environment. The diversity of the properties imparted to the two opposing sides enables the design of new multifunctional materials for applications in a broad variety of fields including opto-electronics, energy storage, and catalysis. In this perspective, we summarize the most enlightening experimental methods for the asymmetric chemical functionalization of 2DMs with tailored made (macro)molecules by means of a supratopic binding (one side) or antaratopic binding (two sides) process. We describe the emergence of unique electrical and optical characteristics resulting from the asymmetric dressing of the two surfaces. Representative examples of Janus 2DMs towards bandgap engineering, enhanced photoresponse and photoluminescence are provided. In addition, examples of Janus 2DMs for real applications such as energy storage (batteries and supercapacitors) and generation (photovoltaics), opto-electronics (field-effect transistors and photodetectors), catalysis, drug delivery, self-healing materials, chemical sensors and selective capture and separation of small molecules are also described. Finally, we discuss the future directions, challenges, and opportunities to expand the frontiers of Janus 2DMs towards technologies with potential impact in environmental science and biomedical applications.