Applications In Energy Storage Devices Research Articles

Experimental and theoretical study of improved mesoporous titanium dioxide perovskite solar cell: The impact of modification with graphene oxide

The present study serves experimental and theoretical analyses in developing a hybrid advanced structure as a photolysis, which is based on electrospun Graphene Oxide-titanium dioxide (GO-TiO2) nanofibers as an electron transfer material (ETMs) functionalized for perovskite solar cell (PVSCs) with GO. The prepared ETMs were utilized for the synthesis of mixed-cation (FAPbI3)0.8(MAPbBr3)0.2. The effect of GO on TiO2 and their chemical structure, electronic and morphological characteristic were investigated and discussed. The elaborated device, namely ITO/Bl-TiO2/3 wt% GO-TiO2/(FAPbI3)0.8(MAPbBr3)0.2/spiro-MeTAD/Pt, displayed 20.14% disposition and conversion solar energy with fill factor (FF) of 1.176%, short circuit current density (Jsc) of 20.56 mA/cm2 and open circuit voltage (VOC) 0.912 V. The obtained efficiency is higher than titanium oxide (18.42%) and other prepared GO-TiO2 composite nanofibers based ETMs. The developed materials and device would facilitate elaboration of advanced functional materials and devices for energy storage applications.

Peptide‐Based Assemblies for Supercapacitor Applications

The increased focus on green energy storage devices and the related rapid advancement in biomedical technologies makes the investigation of biocompatible integrated systems with medical relevance increasingly important. Peptides and their assembled morphologies with their innate biocompatibility and biodegradability are emerging as promising candidates in this respect due to their structural attributes which can be easily tuned to form supramolecular 3D architectures with extended pathways for ionic mobility. However, to comprehend their applicability in energy storage devices, it is crucial to explore their self‐assembling characteristics, charge‐storage mechanisms, and coating efficacies. Herein, all these aspects are compiled with specific emphasis on peptide‐based systems for supercapacitor applications. The electrochemical charge storage mechanisms that are used for categorizing conventional supercapacitors with the theories and mechanisms outlining biological electron transfer, such as tunneling, hopping, superexchange, and flickering resonance, are collated. Furthermore, the characterization techniques solely pertaining to the study of such systems and their role in predicting the morphology of self‐assembly patterns which could directly impact the overall electrochemical properties are also addressed. Finally, some of the critical challenges associated with these systems while realizing their future potential in the field of sustainable energy storage devices are highlighted.

Molybdenum induced defective WO3 multifunctional nanostructure as an electrochromic energy storage device: Novel assembled photovoltaic-electrochromic Mo–WO3 film

In this work, a self-powered electrochromic device incorporating molybdenum-doped tungsten oxide (WO3) is developed for enhanced performances, offering a potential solution for energy efficient technologies. Defective nanostructure of WO3, enabled with molybdenum doping, is achieved through an electrochemical co-deposition method. A film of Mo–WO3 is investigated for multifunctional purposes, acting as both an electrochromic (EC) and energy storage device (ESD). As an EC film, it exhibits an optimal optical contrast of 84.5 %, minimum coloration time of 0.4 s, high coloration efficiency of 90.4 cm2/C, and excellent optical stability. In ESD applications, Mo–WO3 displays charge-transfer resistance of 7.6 Ω, a commendable capacitance of 39.1 mF/cm2, and excellent capacitance retention of 80.4 %. The integration of Mo ions into the WO3 nanostructure results in the formation of oxygen defect sites, which enhances the mobility of Li+ ions over the amorphous and deagglomerated morphology of Mo–WO3. Furthermore, the EC activity of Mo–WO3 film does not require an external power source as the film is powered by an integrated quantum dot-sensitized solar cell (QDSSCs). The open circuit voltage of 0.62 V, resulting from the QDSSCs power source, successfully facilitates the switching operation of the Mo–WO3 EC film.

Novel copper vanadium oxide/g-C3N4 nano-composites for optoelectronic and biosensing properties

This study investigates into the synthesis, characterization, and multifaceted analysis of a composite material comprised of copper vanadium oxide (CVO) and graphitic Carbon Nitride g-C3N4 (GCN). The fabrication of the composite was achieved through wet-chemical method followed by annealing at 600 °C for 3 h, ensuring controlled composition and structure. The characterization process encompassed X-ray diffraction (XRD), scanning electron microscopy (SEM), and UV–visible spectroscopy, unveiling the composite's crystalline structure, novel nano-rod morphology with decorated flakes, and UV–visible light activation capability. The obtained band gap of approximately 2.7 eV signified the composite's optical properties. Electrochemical analysis, including cyclic voltammetry (CV), highlighted the composite's robust biosensing attributes, particularly in response to ascorbic acid. The conducting and metallic characteristics of the composite enhanced its reactivity, promising applications in biosensors and energy storage devices. This comprehensive investigation elucidates the multifaceted potential of the CVO/GCN nano-composite across diverse optoelectronic realms.

Unleashing the power: Superior properties of fluorographene-derived materials for energy storage applications

Fluorographene exhibits a rich chemistry and a wide range of applications in energy storage devices. This review, which is based on our lab results acquired in the last decade, explores the synthesis, properties, and performance of fluorographene-based materials in supercapacitors and batteries. Fluorographene can be prepared through mechanical or chemical delamination of graphite fluoride, allowing for scalable synthesis and further chemical processing. The chemical versatility of fluorographene enables a wide portfolio of chemical reactions, leading to a new class of graphene derivatives. Graphene acid, a product of fluorographene chemistry, exhibits excellent specific capacitance, cycling stability, and rate capability. Hybridizing graphene acid with metal-organic frameworks can achieve even higher energy and power densities. Furthermore, nitrogen-doped graphene derived from fluorographene demonstrates remarkable capacitive behavior, making it an efficient electrode material for supercapacitors. Additionally, fluorographene-based materials, such as graphene acid, graphene-sulfur hybrids, and graphene-based anodes, have exhibited outstanding performance in lithium-ion and lithium-sulfur batteries. The scalable synthesis, high performance, and versatility of fluorographene-derived materials render them attractive for practical energy storage applications. The unique properties and wide range of chemistries offered by fluorographene chemistry open new possibilities for improving advanced energy storage devices.

A simple efficient algorithm for molecular simulations of constant potential electrodes.

Increasingly, society requires high power, high energy storage devices for applications ranging from electric vehicles to buffers on the electric grid. Supercapacitors are a promising contribution to meeting these demands, though there still remain unsolved practical problems. Molecular dynamics simulations can shed light on the relevant molecular level processes in electric double layer capacitors, but these simulations are computationally very demanding. Our focus here is on the algorithmic complexity of the constant potential method (CPM), which uses dedicated electrostatics solvers to maintain a fixed potential difference between two conducting electrodes. We show how any standard electrostatics solver-capable of calculating the energies and forces on all atoms-can be used to implement CPM with a minimum of coding. As an example, we compare our generalized implementation of CPM, based on invocations of the particle-particle-particle-mesh routine of the Large-scale Atomic/Molecular Massively Parallel Simulator, with a traditional implementation based on a dedicated re-implementation of Ewald summation. Both methods yield comparable results on four test systems, with the former achieving a substantial gain in speed and improved scalability. The step from dedicated electrostatic solvers to generic routines is made possible by noting that CPM's traditional narrow Gaussian point-spread of atomic charges on the electrodes effectively endows point-like atoms with chemical hardness, i.e., an intra-atomic energy quadratic in the charge.

Porous pathways: Exploring the future of conducting polymers

AbstractConducting polymers (CPs) possess the intrinsic attractive properties of conventional polymers, coupled with unique electronic characteristics reminiscent of metals or semiconductors. Nanostructured CPs have recently gained significant interest for their distinct advantages over bulk counterparts. They demonstrate potential applications in energy storage devices, sensors, and catalysts, attributed to their large surface areas and shortened charge transport paths. A crucial structural aspect in this context includes introducing porous morphologies into CPs, and enhancing their functionality through interconnected channels. In this review, various synthetic methods of nanostructured CPs are introduced, emphasizing two‐dimensional (2D) configurations. The primary objective is to achieve high‐performance devices with highly organized stacking of conjugated backbones. Particular attention is placed on integrating 2D structures and porous morphologies into CPs through ice‐assisted methods and interfacial synthesis. The review also highlights successful applications of porous 2D CPs in practical devices and explores insights into future developments in the porous CPs field.

Reduced leakage current and enhanced energy storage performance of BZNT/BTO multilayer structures: Implications in electronic devices

The extremely high recoverable energy density (Wrec) and efficiency (η) of lead-free thin films make them a promising candidate for application in miniature power devices. Here, a stable design of multilayered structures of BaTiO3 (BTO) and Bi[Zn2/3(Nb0.85Ta0.15)1/3]O3 (BZNT) have been fabricated using the pulsed laser deposition (PLD) technique on n-type Si, and Pt/Ti/SiO2/Si (Pt-Si) substrates. The effect of a number of stacking of alternate BTO and BZNT layers on the structural, microstructural, electrical, and ferroelectric properties is investigated. The films exhibited a polycrystalline nature, and the tetra-layer stacked film (BZNT/BTO3) exhibited better crystallinity, improvement in microstructure, and grain growth than that of the bi-layer stacked film (BZNT/BTO1). The improvement in ferroelectric response in the tetra-layer film is well correlated to the low leakage current density (∼10-7 A/cm2 at ±500 kV/cm) owing to reduced defects in the film. The reduced oxygen vacancies and dielectric loss tangent of order 10-3 validate the high quality of BZNT/BTO3 film exhibiting a large Wrec of 52.19 J/cm3 and high energy efficiency of 92.21 % achieved through interface engineering. These findings demonstrate the promising future for BTO-based multilayer thin film in high-power and energy-storage device applications.

Flexible wearable energy storage devices: Materials, structures, and applications

AbstractWearable electronics are expected to be light, durable, flexible, and comfortable. Many fibrous, planar, and tridimensional structures have been designed to realize flexible devices that can sustain geometrical deformations, such as bending, twisting, folding, and stretching normally under the premise of relatively good electrochemical performance and mechanical stability. As a flexible electrode for batteries or other devices, it possesses favorable mechanical strength and large specific capacity and preserves efficient ionic and electronic conductivity with a certain shape, structure, and function. To fulfill flexible energy‐storage devices, much effort has been devoted to the design of structures and materials with mechanical characteristics. This review attempts to critically review the state of the art with respect to materials of electrodes and electrolyte, the device structure, and the corresponding fabrication techniques as well as applications of the flexible energy storage devices. Finally, the limitations of materials and preparation methods, the functions, and the working conditions of devices in the future were discussed and presented.

Uniformly distributed FeVO4 nanocuboids on exfoliated rGO facilitated by supersonic spraying for wearable supercapacitors

High-energy–density supercapacitors exhibiting high power density and long-term stability are essential devices for energy storage applications, such as wearable electronics. In this study, we utilized supersonic spray deposition to exfoliate reduced graphene oxide (rGO). Additionally, a solvothermal process was employed to engineer the nanostructure of iron/vanadium oxides. Consequently, the resulting multivalent iron/vanadium oxide and rGO composites exhibited remarkably high energy densities. Three major parametric studies were conducted to investigate the electrochemical properties of iron oxide (FO), vanadium oxide (VO), and iron/vanadium oxide (FVO) composites with rGO. FVO/rGO emerged as the most promising sample, exhibiting an areal capacitance of 1240 mF·cm−2 at a current density of 2 mA·cm−2, as well as achieving a 90 % capacitance retention even after 8000 galvanostatic charge–discharge cycles. Furthermore, this sample delivered an energy density of 0.17 mWh·cm−2 at a power density of 4 mW·cm−2.

N/O co-doped porous carbon synthesized by lewis acid salt activation for high rate performance supercapacitor

Cellulose derivatives are widely used as carbon precursors for porous carbon materials because of their high carbon contents and low cost. Herein, N/O co-doped porous carbon materials were synthesized from sodium carboxymethyl cellulose by one-step carbonization and activation with zinc nitrate hexahydrate, a lewis acid salt, as the chemical foaming agent and activation agent and urea as the nitrogen source. The nitrogen content and oxygen content of the optimized sample reached 7.6 at.% and 12.7 at.%, respectively, and the specific surface area reached 1318 m2 g−1. The doping of nitrogen element increased the specific capacitance by nearly two times. In a three-electrode system, the maximum specific capacitance reached 234 F g−1 at 0.1 A g−1 in 6 M KOH electrolyte. The maximum energy density of symmetric supercapacitor was 15.7 Wh kg−1 at the power density of 497.3 W kg−1. The capacitance retention maintained 90.3 % after 10,000 cycles at 20 A g−1. This work provides a novel method for the preparation of porous carbon materials derived from sodium carboxymethyl cellulose and expands its application in energy storage devices.

Amorphous Magnesium-Doped Chitosan films as solid polymer electrolytes for energy storage device applications

Magnesium ion-conducting biodegradable solid polymer electrolyte (SPE) films of magnesium perchlorate [Mg(ClO4)2] doped Chitosan [CS] were prepared using the solution casting technique at room temperature. XRD study shows that amorphous nature of the polymer matrix increases upon doping. FTIR deconvolution confirm the complexation generated between the salt and the polymer. The current–voltage measurement exhibited electrochemical stability window for all samples above 2.14 V. The ionic transference number for the highest conducting sample was 0.99. The impedance analysis was done for each SPE film, and the sample with the highest concentration (40 wt%) exhibited the highest conductivity, 5.7 × 10-4 Scm−1. The prepared primary magnesium battery using the highest conducting SPE showed open circuit potential of 2.112 V. Due to its exceptional qualities, this prepared electrolyte may be a strong contender for energy storage systems.

Rapid microwave-assisted synthesis and characterization of a novel CuCoTe nanocomposite material for optoelectronic and dielectric applications.

In the realm of nanomaterial research, copper telluride and cobalt telluride have individually attracted considerable attention owing to their unique properties and potential applications. However, there exists a notable gap in the literature when it comes to the exploration of composite materials derived from these elements. From this point of view, a ternary CuCoTe nanocomposite was prepared using the microwave synthesis method. Various characterizations were performed by varying the power and irradiation time. X-Ray diffraction study and transmission electron microscopy analysis confirmed the polycrystalline nature of the material with Cu2Te and CoTe hexagonal phases. Field emission scanning electron microscopy images reveal nanoparticle-like morphology, which remains unchanged even when the time of irradiation increases. In addition, the nanoparticle size of the material lies in the range of 30-39 nm. The differential scanning calorimetry inferred various exothermic and endothermic peaks. Meanwhile, the optical analysis from the UV-visible study shows the red-shifted absorbance, enabling the material for semiconductor and photovoltaic devices. Furthermore, the optical bandgap of the material varies in the range from 2.45 to 3.61 eV, which reveals the tuneable bandgap desiring the material for various optoelectronic applications. The frequency-temperature-dependent dielectric study gives results for dielectric parameters, conductivity, and impedance behaviour. The material's dielectric constant, dielectric loss, and AC conductivity enhance with the increase in temperature. This behaviour of the material broadens the area of applicability in energy storage devices.

Recent advances on COF-based single-atom and dual-atom sites for oxygen catalysis.

Covalent organic frameworks (COFs) have emerged as promising platforms for the construction of single-atom and dual-atom catalysts (SACs and DACs), owing to their well-defined structures, tunable pore sizes, and abundant active sites. In recent years, the development of COF-based SACs and DACs as highly efficient catalysts has witnessed a remarkable surge. The synergistic interplay between the metal active sites and the COF has established the design and fabrication of COF-based SACs and DACs as a prominent research area in electrocatalysis. These catalytic materials exhibit promising prospects for applications in energy storage and conversion devices. This review summarizes recent advances in the design, synthesis, and applications of COF-based SACs and DACs for oxygen catalysis. The catalytic mechanisms of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are comprehensively explored, providing a comparative analysis to elucidate the correlation between the structure and performance, as well as their functional attributes in battery devices. This review highlights a promising approach for future research, emphasizing the necessity of rational design, breakthroughs, and in-situ characterization to further advance the development of high-performance COF-based SACs and DACs for sustainable energy applications.

Polypyrrole in-situ polymerized MXene/TPU fiber electrode for flexible supercapacitors

Ti3C2Tx-based flexible fibers have great potential and wide applications in the energy storage field of wearable electronic textiles and portable electronic devices. This work reports a Ti3C2Tx-MXene/TPU/polypyrrole(PPy) fiber in which PPy is grown on the surface of Ti3C2Tx/TPU fiber by in-situ polymerization. Through efficient wet spinning and in-situ polymerization, Ti3C2Tx/TPU/PPy fiber exhibit pore structure and abundant active sites, which significantly enhance charge transfer rate and conductivity. The fiber exhibits a capacitance of 41.2 F g−1(5 mV S−1) and excellent rate performance in 1 M H2SO4 electrolyte. Its symmetrical fiber-based flexible supercapacitors(SCs) can provide an energy density of 2.36 mW h g−1. At the same time, the fiber has good flexibility and can be woven into a fabric SCs as a wearable energy storage device to realize power supply applications such as electronic watches and LEDs, which provides a potential strategy for the application of flexible wearable energy storage devices.

Towards the 4 V-class n-type organic lithium-ion positive electrode materials: the case of conjugated triflimides and cyanamides.

Organic electrode materials have garnered a great deal of interest owing to their sustainability, cost-efficiency, and design flexibility metrics. Despite numerous endeavors to fine-tune their redox potential, the pool of organic positive electrode materials with a redox potential above 3 V versus Li+/Li0, and maintaining air stability in the Li-reservoir configuration remains limited. This study expands the chemical landscape of organic Li-ion positive electrode chemistries towards the 4 V-class through molecular design based on electron density depletion within the redox center via the mesomeric effect of electron-withdrawing groups (EWGs). This results in the development of novel families of conjugated triflimides and cyanamides as high-voltage electrode materials for organic lithium-ion batteries. These are found to exhibit ambient air stability and demonstrate reversible electrochemistry with redox potentials spanning the range of 3.1 V to 3.8 V (versus Li+/Li0), marking the highest reported values so far within the realm of n-type organic chemistries. Through comprehensive structural analysis and extensive electrochemical studies, we elucidate the relationship between the molecular structure and the ability to fine-tune the redox potential. These findings offer promising opportunities to customize the redox properties of organic electrodes, bridging the gap with their inorganic counterparts for application in sustainable and eco-friendly electrochemical energy storage devices.

Ordered mesoporous carbon with binary CoFe atomic species for highly efficient oxygen reduction electrocatalysis.

The exploration of powerful, efficient and precious metal-free electrocatalysts for facilitating the sluggish kinetics of the oxygen reduction reaction (ORR) is a crucial endeavor in the development and application of energy conversion and storage devices. Herein, we have rationally designed and synthesized bimetallic CoFe species consisting of CoFe nanoparticles and atomically dispersed dual atoms anchored on an ordered mesoporous carbon matrix (CoFe/NC) as highly efficient ORR electrocatalysts. The pyrolyzation temperature for CoFe/NC plays a vital role in regulating the morphology and composition of both the carbon matrix and CoFe species. The optimized CoFe/NC-750 exhibits a favorable ORR performance in 0.1 M KOH with a high half-wave potential (E1/2) of 0.87 V vs. RHE, excellent tolerance to methanol and remarkable durability (no obvious decrease in E1/2 value after 3000 cycles), all of which are superior to the performance of commercial Pt/C. Experimental measurements and density functional theory (DFT) calculations reveal that the improved ORR performance of CoFe/NC-750 is mainly attributed to the electronic structure of atomically dispersed Fe active sites modulated by the surrounding CoFe alloys and Co single atoms, which accelerates the dissociation and reduction of intermediate OH* species and promotes the ORR process.

In situ growth of a redox-active metal-organic framework on electrospun carbon nanofibers as a free-standing electrode for flexible energy storage devices.

The rational construction of free-standing and flexible electrodes for application in electrochemical energy storage devices and next-generation supercapacitors is an emerging research focus. Herein, we prepared a redox-active ferrocene dicarboxylic acid (Fc)-based nickel metal-organic framework (MOF) on electrospun carbon nanofibers (NiFc-MOF@CNFs) via an in situ approach. This in situ approach avoided the aggregation of the MOF. The NiFc-MOF@CNF flexible electrode showed a high redox-active behavior owing to the presence of ferrocene and flexible carbon nanofibers, which led to unique properties, including high flexibility and lightweight. Furthermore, the prepared electrode was utilized in a supercapacitors (SC) without the use of any binder, which achieved a specific capacity of 460 C g-1 at 1 A g-1 with an excellent cyclic retention of 82.2% after 25 000 cycles and a good rate capability. A flexible asymmetric supercapacitor device was assembled, which delivered a high energy density of 56.25 W h kg-1 and a long-lasting cycling performance. Also, the prepared electrode could be used as a freestanding electrode in flexible devices at different bending angles. The obtained cyclic voltammetry curves showed negligible changes, indicating the high stability and good flexibility of the electrode. Thus, the use of the in situ strategy can lead to the uniform growth of redox-active MOFs or other porous materials on CNFs.

A detailed investigation of rare earth lanthanum substitution effects on the structural, morphological, vibrational, optical, dielectric and magnetic properties of Co-Zn spinel ferrites.

In this work, Co0.5Zn0.5LaxFe2-xO4 (0.00 ≤ x ≤ 0.10) spinel ferrites were synthesized using the sol-gel auto-combustion method. X-ray diffraction (XRD) analysis and Rietveld refinement confirmed the presence of a cubic spinel structure. The crystallite size was estimated to be between 17.5nm and 26.5nm using Scherrer's method and 31.27 nm-54.52nm using the Williamson-Hall (W-H) method. Lattice constants determined from XRD and Rietveld refinement ranged from (8.440 to 8.433Å and 8.442 to 8.431Å), respectively. Scanning electron microscopy (SEM) revealed a non-uniform distribution of morphology with a decrease in particle size. The bandgap values decreased from 2.0eV to 1.68eV with increasing rare earth (La3+) doping concentration. Fourier-transform infrared (FT-IR) spectroscopy confirmed the presence of functional groups and M-O vibrations. The dielectric constant and dielectric loss exhibited similar behavior across all samples. The maximum tan δ value obtained at lower frequencies. Regarding magnetic behavior, there was a decrease in magnetization from 55.84 emu/g to 22.08 emu/g and an increase in coercivity from 25.63Oe to 33.88Oe with higher doping concentrations. Based on these results, these materials exhibit promising properties for applications in microwave and energy storage devices.

First-principles study of the oxidation susceptibility of WS2, WSe2, and WTe2 monolayers.

The environmental stability of two-dimensional (2D) transition metal dichalcogenide monolayers is of great importance for their applications in electronic, photonic, and energy storage devices. In this study, we focus on understanding the susceptibility of WS2, WSe2, and WTe2 monolayers to oxygen exposure in the form of atomic oxygen and O2 and O3 molecules, respectively. Calculations based on the van der Waals-corrected density functional theory predicted that O2 and O3 molecules are weakly adsorbed on these monolayers, although atomic oxygen prefers chemisorption accompanied by a significant charge transfer from the surface to oxygen. In the physisorbed molecular configurations consisting of O2 and O3, the partially oxidized monolayers retain their geometrical and electronic structures. The calculated transition path as the oxygen approaches the surface shows a high-energy barrier for all cases, thus explaining the photo-induced formation of the oxidized configurations in the experiments. Furthermore, oxidizing the WS2 monolayer is predicted to modify its electronic structure, reducing the band gap with increasing oxygen coverage on the surface. Overall, the calculated results predict the resilience of WS2, WSe2, and WTe2 monolayers against oxygen exposure, thus ensuring stability for devices fabricated with these monolayers.