Supercapacitor Device Research Articles

A flexible solid-state asymmetric supercapacitor device comprising cobalt hydroxide and biomass-derived porous carbon.

Development in the field of alternative and renewable energy sources is becoming necessary considering the current energy demands of the growing technologies. The main challenge associated with the produced energy is to store it for future use, such that it can be used when needed. Supercapacitors are among the electrochemical energy storage systems that provides higher power density, faster charging-discharging, high specific capacitance (C S), and long cycling life. Herein, the fabrication of a flexible solid-state asymmetric supercapacitor (ASC) device is reported, where Co(OH)2 hollow spheres and biomass-derived porous carbon (PC) are the cathode and anode, respectively. Co(OH)2 is a highly redox active material, whereas PC is an electric double-layer capacitive (EDLC) material. In this device, aqueous KOH solution (electrolyte) encapsulated in PVA gel (separator) was used to bind the electrodes. This Co(OH)2//PC ASC device exhibited a high C S of 260 F g-1 (at 2 A g-1). It retained ∼91% of the initial C S value (at 6 A g-1) till ∼5000 cycles. Electrochemical impedance spectroscopy (EIS) study confirmed low internal resistance (0.95 Ω) and charge transfer resistance (1.41 Ω) values of Co(OH)2//PC. These results indicate that the high electron transfer process in the electrode-electrolyte interface during the electrochemical reaction, which is responsible for the excellent performance of this ASC device. The high-performance Co(OH)2//PC ASC device exhibited an energy density of 76.7 W h kg-1 at a power density of 1416.9 W kg-1. To demonstrate its practical use, LED lights were illuminated using this Co(OH)2//PC ASC device.

One-step microwave synthesis of in situ grown NiSe microdendrite arrays on Ni foam for high-performance supercapacitors

The strategic design of in situ grown nanomaterials with microdendrite morphology to enhance supercapacitor performance has become a significant research focus in the field of renewable energy storage. This study explores an innovative one-step microwave technique for producing different NiSe microdendrite arrays that are grown in situ on Ni foam (NF) substrates. In this process, Ni foam serves dual roles as a Ni source and a structural framework. At a current density of 0.6 A g−1, NiSe microdendrite arrays that were synthesized demonstrate a capacity of 261.1 mAh·g−1, surpassing that of the majority of traditional pseudocapacitive materials. Furthermore, the effect of the solvent, Se powder dosage, and microwave reaction parameters on the micromorphology and electrochemical properties of NiSe is comprehensively examined. Furthermore, the supercapacitor device featuring a positive electrode composed of NiSe microdendrite arrays and a negative electrode constructed from activated carbon (AC) exhibits a broad voltage range of 1.7 V. It also achieves a peak energy density of 50.29 Wh·Kg−1 at power density of 847.98 W kg−1, suggesting a promising application prospect.

Microwave-assisted synthesis of perovskite hydroxide-derived Co3O4/SnO2/reduced graphene oxide nanocomposites for advanced hybrid supercapacitor devices

The current article reports a facile, ultrafast, and cost-effective, solid-state microwave (MW) synthetic route for the conversion of perovskite hydroxide (CoSn(OH)6) to crystalline metal oxides (Co3O4 and SnO2) with the help of reduced graphene oxide (rGO) nanosheets. In a domestic MW oven, the Co3O4/SnO2/rGO (CSO-rGO) nanocomposite was synthesized within a quick reaction time of only 30 s. The study deeply focused on analyzing the surface morphology, metal oxide attachment on the surfaces of rGO nanosheets, the specific surface area, and the electrochemical performance of supercapacitor devices from the CSO-rGO nanocomposite. As a positive electrode for supercapacitors, the synthesized hybrid electrode displayed a good capacity (146.4C/g) and enhanced cycling stability (103.2 % after 15,000 cycles). Moreover, the corresponding aqueous hybrid supercapacitor device with MW-synthesized rGO as a negative electrode displayed a maximum energy density of 27 Wh/kg and promising cycling stability of 102.4 % after 10,000 cycles. As a whole, compared to the common time-consuming synthetic approaches, the MW-assisted synthetic approach is highly beneficial in terms of short reaction time, cost-effectiveness, and straightforwardness. The MW synthesis methodology employed in this study can be utilized for analogous composite electrodes that incorporate other layered conductive architectures in addition to metal oxides.

Synthesis and electrochemical characterizations of RGO-decorated MnO2 nanorods/carbon cloth-based wearable symmetric supercapacitors

The current research explores a facile two-step method for fabricating flexible RGO-decorated MnO2 nanorod electrodes on a carbon cloth substrate, ideal for wearable energy storage devices. The strategy involves first depositing MnO2 nanorods on the carbon cloth utilizing a hydrothermal technique, followed by a simple ex-situ decoration with reduced graphene oxide by varying concentrations. Through comprehensive physical and electrochemical analyses, the impact of different concentrations of graphene oxide on the physical and electrochemical characteristics of MnO2 electrodes is thoroughly examined. Among the investigated concentrations of graphene oxide, the RGO-decorated MnO2 electrode featuring a 20 mg/100ml concentration of graphene oxide showcased the maximum specific capacitance reaching 1072.28 F/g at a 5 mV/sec in a 1M Na2SO4 electrolyte. Furthermore, this electrode demonstrated commendable long-term cycle stability, preserving over 87% of its original capacitance after enduring 2000 cycles of charge and discharge. A symmetric prototype supercapacitor device has been constructed to assess their practical utility utilizing symmetric electrodes and an aqueous electrolyte. This symmetric device exhibits promising electrochemical properties, underscoring the potential of the developed electrodes for real-world implementation. The remarkable structural, morphological, and electrochemical characteristic attributes of RGO-decorated MnO2 nanorods grown on the carbon cloth substrate position them as superior electrode materials tailored for the burgeoning realm of wearable energy storage devices, paving the way for advanced flexible and efficient energy storage solutions.

Porous Carbon Electrode from Starch Soluble for Realizing High‐Performance Supercapacitor

AbstractOrganic potassium salts are the promising green activators for synthesizing porous carbon materials for energy storage. Herein, we report the synthesis of hierarchical porous carbon material derived from the mixture of soluble starch and ethylenediaminetetraacetic acid dipotassium salt dihydrate (EDTA‐2K) via carbonization and activation strategy. The sample is used as supercapacitors electrode, which exhibits superior mass specific capacitance (307.3 F g−1 at 1 A g−1), good rate performance (255.0 F g−1 at 10 A g−1), and excellent stability (retaining 83 % after 15000 cycles). This enhanced electrode performance is mainly due to the high specific surface area, the heteroatom co‐doping providing pseudo‐capacitance and the improved electronic conductivity. In addition, the asymmetric supercapacitor device shows a high energy density of 15 Wh kg−1 at the power density of 800 W kg−1 and capacitance retention of 90 % after 12000 cycles.

Evolution of CuO bundles of nanowires by room temperature surface oxidation of electroplated Cu for high-performing energy storage device

In the present work, copper oxide bundles of nanowires (CuO BNWs) were synthesized by room-temperature surface oxidation of an electroplated Cu layer in an alkaline bath. The time-dependent morphological evolution of CuO BNWs is systematically achieved by varying surface oxidation times. The CuO BNWs provide a high surface area (19.12 m2/g) and have shown excellent supercapacitive performance with a specific capacitance of 509 F/g at 1 A/g current density owing to fast electron transfer paths offered by BNWs. The all-solid-state hybrid supercapacitor device (SS//Cu//CuO-BNWs//KOH-PVA//rGO) demonstrates a specific capacitance of 77.3 F/g and energy density of 22.57 Wh/kg at a power density of 1.29 kW/kg.

Boosting supercapacitor performance synergistically with Bi2O3/MnO2:rGO nanocomposites and redox additive electrolyte

The contemporary surge in energy demand underscores the imperative for improvements in energy conversion and storage technologies. In response, supercapacitor devices were engineered using nanocomposites (NCs) of Bi2O3/MnO2:rGO (BMR), and their electrochemical performance was systematically documented. The BMR NCs were hydrothermally prepared and their physicochemical characteristics were analyzed. The working electrode was constructed employing BMR NCs, and tested in a three-electrode setup to explore its electrochemical properties using the aqueous electrolytes consisted of 1 M KOH and 0.1 M K4[Fe(CN)6] added 1 M KOH (referred as Redox additive electrolyte - RAE). BMR NCs loaded working electrode exhibited 1441.1 Fg−1 of specific capacitance at 5 mVs−1 in RAE. Subsequently, asymmetrical supercapacitor devices were assembled, incorporating a cathode comprised of BMR NCs modified Ni foam and rGO-loaded Ni foam as an anode. The supercapacitor performances were evaluated using KOH and RAE in a two-electrode setup. The BMR NCs loaded supercapacitors demonstrated 9.42 Whkg−1 and 2100 Wkg−1, of energy and power densities, respectively, in KOH. Obtained energy and power density values were improved to 16.08 Whkg−1 and 2800 Wkg−1, respectively, by the utilization of RAE. Since the synthesized BMR NCs exhibited superior performances in RAE, the suggested combination of BMR NCs and RAE emerged as a more promising option for energy storage applications in real-time.

A novel benzoquinone‐azo linked polymer‐based active electrode material for high‐performance symmetric pseudocapacitors

AbstractPseudocapacitors (PSCs) have attracted researcher's attention due to their potential electrochemical performance as the power source for electronic devices. However, to maintain the high electrochemical properties of pseudocapacitive materials becomes critical. Therefore, the active electrode materials design and synthesis is a challenging task. To tackle these problems, herein, we rationally designed new polymer based on benzoquinone with azo linker. The polymer AZO‐BQ‐P was synthesized and tested for their energy storage applications in combination with graphite foil (GF). In three‐electrode supercapacitor (SC) device, the AZO‐BQ‐P/GF electrode exhibits excellent specific capacitance (Csp) of about 306.27 F g−1 at 0.5 A g−1 current density and higher cycling stability. The pseudocapacitive performance of SC cells result from synergistic effect of AZO‐BQ‐P and GF and due to faster electrolyte ion diffusion and increased availability at electrode/electrolyte interfaces. Furthermore, AZO‐BQ‐P/GF electrode was employed to fabricate two‐electrode AZO‐BQ‐P/GF//AZO‐BQ‐P/GF symmetric SC device. The optimal SSC device shows a Csp reaching 200 F g−1 at 0.5 A g−1, which is an impressive value. Also, it exhibits remarkable cycling stability with 86.18% Csp retention after 5000 galvanostatic charging–discharging (GCD) cycles at 3 A g−1. The SSC device applying AZO‐BQ‐P/GF electrode delivers an excellent energy density (ED) of 25.00 Wh kg−1 at 900.00 W kg−1 power density (PD). Thus, the novel polymer design offers efficient electrode materials to enhance the pseudocapacitive electrochemical performance of the SSC device. This concept can be extended for fabricating other electrochemical systems and accelerate its applications for modern electronic devices.

Nitrogen and phosphorus enriched nanoporous carbonaceous material for gas sorption and supercapacitor applications

Nitrogen and phosphorous-enriched heteroatoms-based nanoporous carbonaceous material (designated as HPHMC900) possesses a high surface area of 1668 m2 g−1 was synthesized. HPHMC900 captures 5.6 and 3 mmol g−1 of CO2 and CH4 at 273 K and 1 bar, respectively. Further, the material has 11.95 mmol g−1 of H2 adsorption capability at 77 K and 1 bar. HPHMC900 has been investigated for supercapacitor application. Further, a symmetric supercapacitor device (SSD) fabricated using the HPHMC900, has a specific capacitance (Csp) of 233 F g−1, energy (E) of 46.6 Wh kg−1, and power (P) of 289 W kg−1, respectively. The high Csp and high energy were achieved at low-concentrated aqueous electrolyte (0.5 M KOH), without using any redox-active agents. Further, it shows 100 % coulombic efficiency and initial capacitance retention (94.9 %) after 10,000 cycles. This research elucidates the correlation between high surface area and heteroatom enrichment with enhanced charge storage and gas adsorption efficiency.

Effect of calcination time on modulating the properties of battery type NiMn2O4 intended for supercapacitor applications

In this study, the synthesis of nanostructured NiMn2O4 is achieved through the novel wet-chemical reduction synthesis method, maintained at a constant temperature of 500 °C. Variations in calcination time to 4, 5, and 6 h, with a constant synthesis temperature, result in the formation of NiMn2O4 (NMO) nanostructures (NSs). These NMO-NSs are employed as electroactive materials in the assembly of electrochemical supercapacitors. Electrodes, composed of NMO-NSs calcined for 4 h, at constant temperature of 500 °C, are observed to exhibit a high specific capacitance/capacity of 966.7 F g−1 (579 C g−1) respectively, at a scan rate of 5 mV s−1. Retention of 96 % of the specific capacitance is noted after 5000 cycles of the as optimum electrode (NM-4 h). The significant influence of calcination time on the efficiency of electrochemical supercapacitors is highlighted in this research. An asymmetric supercapacitor device (ASSCs), featuring a wide working potential window of 0–1.6 V and a energy density of 38.9 W h kg−1 at a power density of 5 kW kg−1. As fabricated ASSCs demonstrates high specific capacitance of 109.4 F g−1/175 C g−1 with capacitance retention of 79.9 % over 5000 cycles. The potential of highly porous binary NiMn2O4 NSs as suitable materials for high-performance supercapacitor devices is suggested by the findings.

Nitrogen-doped porous carbon-tubes decorated with Co/CoO nanocomposite material derived from covalent organic framework for energy storage application

In this work, we presented a novel nitrogen-doped porous carbon-tubes (NPCT) decorated with Co/CoO nanohybrid material, synthesized via pyrolysis of cobalt ion-doped covalent organic framework (COF) at temperatures ranging from 800 to 1100 °C in the inert atmosphere. Among the various temperatures, Co/CoO-NPCT-10 (pyrolyzed at 1000 °C) shows higher degree of graphitization and crystallinity essential for the electrochemical performance. TEM images reveal the morphology of the synthesized nanohybrids i.e., tube-like NPCT attached to the spherically shaped Co/CoO. This specific morphology enhances the capacitive behavior of the hybrid materials, and mainly the Co/CoO-NPCT-10 material showed specific capacitance (Cs) of 305 F g−1 at a current density of 1 A g−1 and retained its capacitance with a loss of 6 % at the end of 6000 cycles at 10 A g−1 current density. Co/CoO-NPCT-10 (positive electrode) and CCOF-900 i.e., the COF obtained by carbonization at 900 °C (negative electrode) were used to fabricate an asymmetric supercapacitor device, and showed the Cs of 286 F g−1 at a current density of 1 A g−1. Ragone plot presents the energy density (21 Wh kg−1) and power density (543 W kg−1), respectively, demonstrating its potential use in future energy storage applications.

One-pot synthesis of tungsten oxynitride/nitrogen-doped graphene with particle-sheet hybrid nanostructure as a highly effective binder-free supercapacitor electrode

High-performance nanoscale composites have achieved predominance as promising materials for supercapacitor applications. Graphene nanosheets decorated with transition metal oxynitride nanoparticles can be highly beneficial in improving supercapacitor properties. However, they are hardly retrieved, and their electrochemical characterizations and inherent charge-storage mechanisms have not been deeply investigated. Herein, tungsten oxynitride decorated nitrogen-doped graphene (WON-NG) is synthesized by a facile one-pot strategy in a particle-sheet hybrid nanostructure. The nanocomposite is grown directly on a nickel foam (NF) as the current collector through the synthesis process. X-ray photoelectron spectroscopy and TEM images have confirmed the particle-sheet hybrid nanostructure of the prepared nanocomposite with tungsten oxynitride nanoparticles and nitrogen-doped graphene nanosheet. The oxygen and nitrogen-based redox groups, which synergistically coexist in the hybrid network, inherently cooperate in the electrochemical activities of the nanocomposite. The electrochemical measurements show that the WON-NG|NF electrode can deliver a superior specific capacitance of 1079.4 F g−1 (4.6 F cm−2) at 1 A g−1 in 1 M KOH aqueous electrolyte. In-depth investigations suggest that the diffusive-controlled process governs the charge storage mechanism at all scan rates in the composite for the advantageous porous morphology. The assembled all-solid-state asymmetric supercapacitor device exhibits a high energy density of 81.6 Wh kg−1 and a power density of 5005.4 W kg−1. Also, the designed devise shows an excellent cycle life with 87.7% capacitance retention of 10,000 cycles.

Zeolitic imidazolate framework derived stellate shaped cobalt-molybdenum hybrid sulfide microflower for enhanced supercapacitor properties

Zeolitic imidazolate frameworks (ZIFs) represent a class of material exhibiting a well-defined geometry. The ZIF derivatives are known to inherit the parent morphology and have emerged as a potential platform for developing superior electrode materials. In this study, leaf-like ZIF-67 is synthesized using a chemical route and employed as the sacrificial template in one-pot hydrothermal sulfurization for preparing Co3S4-Mo15S19, cobalt‑molybdenum hybrid sulfide (CMS/NF). The unique stellate-shaped architecture of the CMS/NF microflowers enhances the exposure of the redox active sites, improving charge storage and exhibiting superior performance. On account of the synergy of the metal ions and stellate-shaped hierarchical architecture, the CMS/NF hybrid sulfide shows an excellent specific capacitance value of 3283 F g−1 at a current density of 1 A g−1 with capacitance retention of 77.7 % at 10 A g−1. An asymmetric supercapacitor device based on CMS/NF hybrid sulfide with aqueous KOH electrolyte exhibits a high specific energy of 40.8 Wh kg−1 at 400 W kg−1 with excellent cycling life of 81 % after 5000 cycles with ∼100 % coulombic efficiency. In addition, the density functional theory-based simulations have been carried out for the Co3S4-Mo15S19 hybrid system to develop a better understanding. From the total density of states, it is concluded that compared to the pristine structures, the hybrid system has enhanced states close to the Fermi level, confirming the conductivity improvement. Computed quantum capacitance for the pristine and hybrid systems corroborates the experimental capacitance consequences. Hence, the theoretical examinations warrant our electrochemical results and provide insight into developing high-performance supercapacitor electrodes.

Fabrication and characterization of Sb2O3–MoS2 nanocomposites for high performance supercapacitor applications

Binary nanocomposite-based electrodes have been studied extensively in recent times owing to their multiple oxidation states, excellent physico-chemical features, and combined morphology, which are suitable for increasing the electrochemical performance of supercapacitors. The present work deals with Sb2O3–MoS2 nanocomposites electrode for supercapacitor applications. The x-ray diffraction (XRD), Raman, scanning electron microscope (SEM), energy dispersive x-ray (EDX), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED) and x-ray photoelectron spectroscopy (XPS) characterizations have been studied to analyze the phase formation, vibrational modes, morphology, elemental composition and binding energies of the prepared Sb2O3–MoS2 nanocomposites electrode material, as well as their electrochemical measurements such as cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectroscopy (EIS) have been analyzed. The developed Sb2O3–MoS2 nanocomposites electrode provides a high specific capacitance of 454.3 F g−1 at the current density of 1 A g−1. Further, the hybrid supercapacitor device has been constructed which shows 104.04 F g−1 of specific capacitance at 2 A g−1 and manifests a good energy density of 24.42 Wh kg−1 at a power density of 1299.89 W kg−1. Additionally, the hybrid device Sb2O3–MoS2//AC exhibits a good capacitive retention of 90.6% and a coulombic efficiency of 100.45% at 10 A g-1 over 8000 cycles.

Setaria viridis-like hierarchical structure TiN nanofibers for high-performance supercapacitor

A setaria viridis-like TiN nanofibers with hierarchical structure (noted HSTFs) is synthesized via electrospinning and hydrothermal method. The results reveal that the synthesized HSTFs nanofibers belong to the TiN crystalline phase. The surface of the fibers is uniformly distributed with pore-structured nanorods, which have an average diameter of 55 nm. The HSTFs exhibits a higher specific surface area. Comparing to the TFs||TFs symmetric supercapacitor device, the HSTFs||HSTFs device demonstrates a significantly higher specific capacitance of 177 F g−1 at a current density of 10 mA g−1. The enhanced electrochemical performance is attributed to the hierarchical and porous structure of TiN fibers, which provides a larger surface contact area and more active sites. This structure is conducive to the construction of a conductive network and improves the reversible proton insertion and chemisorption of electrolyte-electron. This research presents a promising approach for the design and synthesizes of high-performance supercapacitor materials.

Synthesis and electrochemical performance of CeO2/NiS nanocomposite for enhanced asymmetric supercapacitor device applications

A novel CeO2/NiS nanocomposite, combining the advantageous properties of transition metal sulfides (high conductivity) and rare-earth metal oxides (excellent stability), was successfully synthesized using a simple hydrothermal method. This composite leverage synergistic effects to potentially achieve superior electrochemical performance in supercapacitor applications. To evaluate its suitability for supercapacitors, the electrochemical performance of the CeO2/NiS electrode was comprehensively investigated using a series of techniques, including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD) curves, electrochemical impedance spectroscopy (EIS), and cyclic stability analysis. The results demonstrate that the as-prepared CeO2/NiS electrode exhibits significantly improved supercapacitor performance compared to the bare CeO2 electrode. The CV curves of the CeO2/NiS electrode reveal a high specific capacitance of 825.53 F/g at a low scan rate of 5 mV/s, indicating good charge storage capability. Further insights into the charge storage mechanism were obtained using the Trasatti method. This analysis revealed that the total stored capacitance of the CeO₂/NiS electrode is 1250 F/g, with contributions from both outer surface capacitance (94 F/g) and inner diffusion capacitance (1156 F/g). Notably, the dominant contribution (92.5 %) originates from capacitive processes, highlighting the efficient charge storage at the electrode surface. The CeO2/NiS electrode also demonstrates exceptional rate capability, delivering a specific capacitance (Csp) of 710 F/g at a high current density of 1 A/g. Additionally, it exhibits impressive cycling stability, retaining approximately 96.56 % of its initial capacitance even after undergoing 3000 continuous GCD cycles at a high current density of 10 A/g. These results suggest that the CeO2/NiS composite can maintain its performance during extended charge-discharge cycles, a crucial characteristic for practical supercapacitor applications. Finally, an asymmetric supercapacitor device was fabricated using the CeO2/NiS nanocomposite. This device achieved a specific capacitance of 157 F/g, demonstrating the potential of the CeO2/NiS composite for practical energy storage applications.

Exploration of Local-Structure and Electrochemical Supercapacitive Performance of Hydrothermally Synthesized α-Fe2O3@Mn3O4@G Composite Electrodes

Due to growth in human population and upsurge in the energy needs, researchers have concentrating on the development of novel/advanced electrode materials. Batteries and supercapacitors (SCs) are most significant energy storage technologies present in contemporary gadgets like smartphones, medical equipment’s, electronic devices etc. However, in comparison to SCs, batteries have higher energy densities and lower power. To increase the energy density of SCs, researchers are engaging on developing hybrid SCs based on low-cost metal oxides/carbon based composite electrodes. Herein, we apply a hydrothermal approach to synthesize graphene supported iron and manganese oxide composite for SCs for the first time. The crystalline structure, phase purity, surface morphology, chemical bonding states, elemental composition of the synthesized samples were characterized by XRD, TEM, FE-SEM, XPS and EDS analysis. In addition, XAS (XANES and EXAFS) technique is used to examine the local structure of the composite samples. After confirming all the basic characterizations, the SC electrodes were constructed using synthesized samples, exhibiting a maximum specific capacitance of about 410 F/g at 5 mV/s and 800 F/g at 1 mA/cm2 in an aqueous electrolyte, which is quite higher than that of pristine Fe2O3, pristine Mn3O4, and Fe2O3-Mn3O4 composite electrodes. Furthermore, even after 2,000 cycles, the graphene composite electrode exhibits a capacitance retention of roughly 85% and a coulombic efficiency of nearly 80%. Furthermore, an asymmetric SC device was designed employing graphene composite as the positive electrode and AC as the negative electrode and investigated their performance using CV, GCD, and EIS analyses, These SC device exhibits extraordinary device performance. As a result, the present study provides a new path to fabricate affordable and flexible SC devices for use in real time applications in near future.

Tailoring Multi-Metallic Phosphide Heterostructures for High Energy Density Hybrid Supercapacitors

Transition metal phosphides have emerged as a cost effective and resourceful materials that gained extreme attention in the energy sector due to deliverance of high capacitance as well as good redox ability comparable with other oxide materials, which makes them budding material for next-generation electrochemical energy storage (EES) systems. Thanks to the metal-phosphorous chelate in the structure which probes the storage mechanism in EES systems. The electrochemical performance can be enhanced by combining multi-metals in the phosphide to collectively utilize the individual features which will increase the charge efficiency. Herein, tri-metallic Ni-Co-Mo-P electrode on Ni-foam substrate was prepared using simplified hydrothermal-calcination-phosphorylation process. The introduction of Mo enhances the electronic conductivity in the trimetallic phosphide electrode which is reflected in the increased electrochemical performance in comparison to NiCoP electrode. Although, Ni-Co-Mo-P electrode delivers superior activity compared to oxide and precursor electrode, however, the capacity retention till 10 A/g was observed to be 60%, which is higher than other prepared electrodes. The enhanced charge storage performance can be attributed to increased number of electrochemical surface area facilitating more redox reactions. The asymmetric supercapacitor device is constructed with Ni-Co-Mo-P // rGO that delivered high energy and power density with satisfactory cyclic capability.

Unsuspected Organometallic Fibers Used As Potential Separators for Supercapacitors Device

Since the last decade, the interest of organic frameworks for electrochemical application the been more studied.1 In general, very few works have been found in the literature. We can mainly mention the use of these derivatives in the presence of inorganic materials both to form solid electrolytes or to protect electrodes. For example, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (H4DOTA) has been used to functionalize PVA to coat the surface of the negative electrode in order to suppress its degradation.2 This resulted in the improvement of the electrochemical properties of the LMNO/graphite cell. Recently, Kim et al. reported the addition of 1,4,8,11-tetramethyl-1,4,8,11-tetraazacyclotetradecane to a carbonate-based electrolyte intended to stabilize the Li metal-electrolyte interface by improving the solid electrolyte interphase.3 More recently, Liu et al. reported a novel carbonyl network polymer NP4 used as a cathode material for organic lithium batteries.4 Very few examples of fully organic frameworks used as separators have been reported.Therefore, our investigation to develop new supramolecular metal-based objects via a self-assembly process of molecular bricks will be presented. The work on cyclen derivatives allows to obtain metal complexes very stable able to pack in a well oriented dimension. Cyclen derivatives, in the presence of metal salts such as copper or zinc chlorides and polar solvents such as aliphatic alcohols, have a strong affinity for metals and spontaneously assemble in some conditions.5 In terms of applications, these self-assembled "organometallic" fibers represent an original and relatively easy to access substrate for fabricating 1D organic objects. Moreover, taking advantage of the properties and potentialities of these materials, we format an adequate shape to handle it as a potential separator for application in Energy Storage Systems (ESS).After a presentation of their synthesis and their formatting as potential separators for supercapacitors, preliminary electrochemical studies will be discussed. 1. J. Mater.Chem. A 2016, 4, 16812; ACS Energy let., 2022, 7, 885.2. ACS Appl. Energy Mater., 2021, 4, 128.3. ACS Appl. Matter. Interface, 2022, 14, 35645.4. J. Electoanalytical. Chem. 2023, 117251.5. Chem. Commun. 2010, 46, 1464. Figure 1

Fabrication of solid-state symmetrical supercapacitor device based on constructed novel Gr-Cu-MoO2 disk electrodes based on Co-replacement reactions

The use of graphite-based substrates has attracted the attention of many researchers due to their high-performance capacitive behavior. Graphite Disk (GD) electrodes due to being more robust and capacity than graphite sheets can be used on an industrial scale. In this research, for the first time, by using the co-replacement method as a straightforward and without wasting energy method, MoO2 and Cu nanostructures with particular morphology were in-situ co-replaced on GD substrates based on commercial graphite and Zn-metal powder. The results of the scanning electron microscopy analysis clearly showed the MoO2–Cu nanosheet formed on the porous GD (PGC) electrode, which has caused a tremendous increase in the capacitance and cyclic stability due to the augment in the surface area and synergistic effect of MoO2–Cu nanostructure. Also, different characterization analysis results confirmed the co-replacement of MoO2 and Cu nanostructures onto the PGD electrode. Electrochemical investigation exhibited that this electrode has an extraordinary capacity of 28526 mF/cm2 at 2 mA/cm2 in 1M H2SO4. The investigation of the capacitive behavior of the MoO2–Cu/PGD supercapacitor device showed that the fabricated supercapacitor device has an astonished capacitance of 4916.98 mF/cm2 (145.27 F/g), power of 18017.34 mW/cm2, and energy density of 4154.84 mWh/cm2 at 1 mA/cm2.