Asymmetric Hybrid Supercapacitor Research Articles

Layer-by-layer WS2-Cr heterojunction as a positive working electrode material for high-performance supercapattery applications

This study investigates the impact on the electrochemical performance of pristine sputtered WS2 through the strategic integration of a highly conductive chromium interfacial layer. This study involves the fabrication of two different samples via magnetron sputtering: type I, WS2-sputtered and type II, WS2/Cr (sputtering of Cr as an interfacial layer between sputtered-WS2 and NF). Afterward, structural, topographic and elemental composition of as-synthesized samples were inspected via XRD, SEM, Raman, and EDX. Following this, the energy storage performance were evaluated by employing CV, GCD, and EIS in three and two electrode assembly sequentially. In three electrode testing WS2 and WS2/Cr exhibited the specific capacity (Qs) of 661.79C g−1 and 1600C g−1 at 3 mV/s along with the capacity retention of 61.37 % (WS2) and 83.04 % (WS2/Cr), respectively. Similarly, through GCD WS2 shows the Qs of 637.34C g−1 at 0.8 A/g conversely, WS2/Cr exhibited the Qs of 1220C g−1 at 1.3 A/g. Besides, the WS2/Cr demonstrated long-term longevity (capacity retention of 83.13 %) after 5000 GCD cycles. Based on exclusive electrochemical performance of type II of two samples, an asymmetric battery-type hybrid supercapacitor (WS2/Cr//AC) was fabricated by incorporating WS2/Cr and activated carbon (AC) as working and counter electrodes. WS2/Cr//AC revealed the Qs of 352C g−1 (785F g-1) at 0.7 A/g. Besides, it deliberately delivered 81 Wh kg−1 and 1750 W kg−1 energy and power. The device exhibits excellent cyclic stability by maintaining its capacity after 5000 GCD cycles and illustrated 87.30 % capacity retention. Following that, semi-empirical approach was applied to quantify the capacitive and diffusive currents’ contribution in overall device’s performance. The results highlight that WS2/Cr hold colossal potential to fill the proficiency gap between presently keep-going devices and stern demands of future energy storage applications.

Facile synthesis of MCo2O4(M= Ni, Cu, and Zn) materials for high-performing electrochemical capacitors with robust cyclic stability using redox additive electrolyte

Developing efficient electrochemical capacitors relies heavily on the quality of electrode materials and electrolytes used. This report presents the successful solvothermal synthesis of three cobaltites, NiCo2O4, CuCo2O4, and ZnCo2O4, and their electrochemical performance in a 2M KOH solution. Among the three cobaltites, NiCo2O4 showed the best electrochemical performance with a specific capacity of 178 C/g with FTO (fluorine-doped tin oxide) as the current collector. In addition, the performance of NiCo2O4 was tested in different aqueous electrolytes, including KOH, NaOH, NaCl, and Na2SO4, and the specific capacity was found to vary in the order of 2 M KOH > 2 M NaOH > 2 M NaCl > 2 M Na2SO4. The performance of NiCo2O4 was also assessed in various concentrations of KOH electrolyte (2 M KOH, 3 M KOH, and 4 M KOH), and the best performance was observed in 3 M KOH with a specific capacity of 928.3 C/g with Ni foam as the current collector. Finally, using redox additive electrolytes, the performance of synthesized NiCo2O4 was evaluated in both 3-electrode and 2-electrode systems. No studies have been conducted on the electrochemical performance of NiCo2O4 with KFCN redox additive in a 3 M KOH electrolyte. In the three-electrode system, NiCo2O4 showed a high specific capacity of 1005.5 C/g at 1 A/g, with 167 % capacity retention after 1000 charge-discharge cycles at a high current density of 30 A/g. The NiCo2O4//Activated Carbon asymmetric hybrid supercapacitors in two-electrode systems exhibited a maximum specific capacity of 115.6 C/g and a specific energy density of 85 Wh/kg at a specific current density of 1 A/g. They also showed a capacitive retention of 120% after 5000 charge-discharge cycles. The maximum power density was 13225 W/kg at a current density of 5 A/g while maintaining an energy density of 22 Wh/kg.

Phosphorus-doped carbon nitride for enhanced supercapacitor performance and energy storage applications

Exploiting the advantages of graphitic carbon nitride doped with phosphorus (xP-CN) electrodes were designed for high-performance hybrid asymmetric supercapacitor via facile hydrothermal and thermal decomposition techniques. The structural, surface chemistry, functional and morphological characterizations evidence depict successful phosphorus incorporation in Carbon Nitride (CN). X-ray photoelectron spectroscopy analysis shows that phosphorus (P) atoms have replaced corner carbon atoms in the CN structure. These findings clearly demonstrate that the presence of phosphorus doping improves the electrochemical activity of the electrodes. The designed three-electrode system has a specific capacitance of 189.36 F/g with a current density of 1 A/g. Phosphorus doping has been discovered to play a significant role in improving both specific capacitance and cycling stability. The capacitance retention of the two-electrode solid-state device has 97.2 % after 5000 cycles. These electrochemical evaluations reveal that the xP-CN electrode exhibits superior electrochemical performances than pristine CN. This doping strategy for CN presents a novel and efficient approach for crafting high-performance supercapacitors.

Strength in Unity: Designing of hybrid heterostructure (NiSe2/rGO/PANI) electrode towards high Performance, Flexible, asymmetric supercapacitor device for renewable energy storage

Heterostructure creation has been an effective strategy to synthesise hybrid supercapacitor electrodes by combining materials of various charge storage mechanisms, leveraging the advantages, and minimising the drawbacks of individual materials as separate entities. Herein, a hybrid supercapacitor electrode has been fabricated producing ternary NiSe2/rGO/PANI heterostructure, through simple hydrothermal followed by in-situ polymerisation techniques. Owing to the synergy between the materials, the electrode decorated on a flexible carbonaceous template exhibits a remarkable capacity of 657.36C g−1@1 A g−1 offering excellent stability over 12,000 cycles. Subsequently, a hybrid asymmetric supercapacitor (HASC) constructed using NiSe2/rGO/PANI as a positive electrode and AC as a negative electrode possesses a high energy density of 98.82 Wh kg−1 at a power density of 750.05 W kg−1 with a capacitive retention of 95.04 %. Encasing the complete device with Polydimethylsiloxane (PDMS) mould acting as an energy storage band demonstrates an unaltered device performance at various bending angles of 0° to 135°, which refers to its compatibility in flexible electronics. Further, the practical usefulness of the as-designed prototype has been exhibited by powering several devices such as; Light Emitting Diodes (LEDs) of various colours, homemade windmill, Arduino board, and LCD monitor via charging through a commercial silicon solar panel paving the way to bloom renewable energy conversion and storage.

Architecture of interconnected cubic NiCo2S4 decorated mesoporous carbon with self-doped nitrogen based-hydrogel for high performance hybrid supercapacitor

Although the transition metal sulfides have shown persuasive proof and stellar traits for energy storage applications, their real applications still possess some obstacles such as prolonged ionic and electronic transport. Hence, NiCo2S4 decorated a pyrolyzed hydrogel (NiCo2S4@PHG) via facile synthesis is considered a promising electrocatalyst for energy storage devices. The prepared electrode materials were characterized utilizing different analysis techniques like XPS, XRD, FT-IR, TGA, SEM, TEM, elemental mapping and EDX that reveal the crucial role of the hydrogel pyrolysis in creating a homogenous nitrogen-doped carbon matrix. The as-fabricated 0.5 NiCo2S4@PHG nanocomposite was electrochemically examined in a sealed workstation cell and showed a clear battery-type supercapacitor behavior attributed to various redox reactions, porosity, and conductivity that was enhanced by self-doped nitrogen. In contrast, composites based on nickel and cobalt sulfides individually with pure hydrogel demonstrated the superiority of binary metal composites. The 0.5 NiCo2S4@PHG electrode exposed a marvelous specific capacity of 317.9 mAh g−1 and capacitance of 2728.5 F g−1 at a current density of 1 A g−1. A hybrid asymmetric supercapacitor was established by 0.5 NiCo2S4@PHG (cathode) and activated carbon (AC, anode), which brought large energy and power densities of 32.8 Wh kg−1 and 750 W kg−1, respectively. The fabricated cell manifests ultra-high retention of 82.6% at a current density of 20 A g−1 after 10,000 cycles. These outstanding accomplishments hold significant potential for practical energy storage and conversion applications.

Calcination synthesized and self-assembled “rough bark-like” cobalt pyrophosphate for the high-performance hybrid supercapacitor as cathode materials

Transition-metal phosphate/pyrophosphate always exhibits promising theoretical electrochemical performance and has essential prospects in supercapacitors. In this study, “rough bark-like” Co2P2O7 is successfully synthesized via calcination method using ammonium cobalt phosphate as raw material. By investigating the effect of calcination temperature on the morphology of Co2P2O7, the pure cobalt pyrophosphate piece could be prepared at 600 °C (CPO-600). Due to the unique morphology and mesoporous presence, the CPO-600 exhibits a good affinity and infiltration interface with the electrolyte and displays a specific capacitance of 544 F g−1 at 1 A g−1 in 3 M KOH, which has excellent rate performance. After 10,000 cycles at 20 A g−1, it still maintains the good cycle stability with 81.48 % initial specific capacitance. Furthermore, the hybrid asymmetric aqueous supercapacitor of CPO-600//AC delivers remarkable energy densities of 10.6 Wh kg−1 at power densities of 559 W kg−1. And its gel electrolyte device also provides higher electrochemical properties and good comprehensive performance.

Sr and Fe-Substituted LaMnO3 Perovskite for High-Rate Asymmetric Hybrid Supercapacitors

Perovskite has been getting significant attention in solar cells, photocatalysts, and hybrid supercapacitors. The symmetry or structural stability of ABO3-type perovskite oxides depends mainly on the size of ‘A’ and ‘B’ cations, which determines the material properties. The partial substitution of these cations may be used to tune these properties. The ionic sizes and valence states of the cations play an important role in improving the properties of perovskite. In this study, the substitution of La3+ with Sr2+ with a larger ionic radius and Mn3+ with Fe3+ with a similar ionic radius favored both the crystal symmetry and the mixed ionic-electronic conductivity of the perovskite. Electrodes based on La0.7Sr0.3Mn0.5Fe0.5O3 (LSMFO55) exhibited a faradaic behavior with a specific capacity of 330 C g-1 (92 mAh g-1) at a 12C rate, while this electrode maintained a capacity of 259 C g-1 at 240C (charge or discharge in 15s). Additionally, exohedral carbon nano-onions (CNO) were introduced as a negative electrode to design an asymmetric hybrid supercapacitor (AHS) with a widened cell voltage. The use of CNO as a negative electrode in the AHS improved the rate capability drastically compared to rGO. This device maintained a good energy density even at an extra-high charging rate (600C), owing to its outstanding rate capability. The high-rate performance of the LSMFO55//CNO AHS can be elucidated by successful fabrication with a mixed ionic-electronic conductive positive electrode and a CNO negative electrode. Tuning the electronic and ionic conductivities by cationic substitution and introducing CNO negative electrodes can provide a practical high-rate hybrid device using various perovskites.

Enhancing heterojunction interface charge transport efficiency in NiCo-LDHs@Co/CoO-CNFs for high-performance asymmetric and zinc-ion hybrid supercapacitors

The lack of active groups and poor dispersion of pristine carbon substrates lead to their inability to composite with other materials effectively, so that the electron transfer between them is inefficient. Therefore, in order to design carbon-based composites with high conductivity and electrochemical properties, the electron transfer between them must be enhanced first. Herein, the Co/CoO quantum dots doped carbon nanofiber (Co/CoO–CNF) materials with mesopore, high degree of graphitization and mechanical flexibility are synthesized via an electrospinning method. Then, ultrathin NiCo-LDHs are uniformly loaded on the Co/CoO-CNFs in situ to form NiCo-LDHs@Co/CoO-CNFs. Benefiting from the Fermi energy level difference and heterointerface between Co/CoO-CNFs (EF = −4.44 eV) and NiCo-LDHs (EF = −2.12 eV), electrons can be tansfered rapidly from NiCo-LDHs to Co/CoO-CNFs during the electrochemical reaction, so that NiCo-LDHs@Co/CoO-CNFs exhibit the excellent specific capacitance of 2055 F g−1 at 1 A g−1. When using in a flexible asymmetric supercapacitor, NiCo-LDHs@Co/CoO-CNFs shows a high energy density of 54.0 W h kg−1 at 760.0 W kg−1. Furthermore, assembled as the Zn-ion hybrid supercapacitor, NiCo-LDHs@Co/CoO-CNFs can also display an ultra-high energy density of 108 W h kg−1 at 914.8 W kg−1, as well as outstanding work durability (the capacitance of 98.2 % after 10,000 cycles).

Synthesis of BaO/NiO/rGO nanocomposite for supercapacitor application

Abstract Considering the global energy crisis, alternative energy resources requirement is rising gradually. In light of dwindling energy resources, we turn to renewable alternatives. Storing this energy for future utilization remains a pressing endeavor. The ideal storage device should possess intensified energy density, power density, and cyclic stability. In this study, we have synthesized metal oxide with carbon based material nanocomposite such as BaO/NiO, BaO/NiO/rGO through cost effective co-precipitation method and their comparative performance for supercapacitor application were studied. Various characterizations were taken for the above synthesized material. X-ray diffraction (XRD) study confirmed the material formation and their crystallinity of the nanocomposite. BaO has tetragonal structure which was confirmed through JCPDS card number 26-0178 and NiO has rhombohedral structure which was confirmed through JCPDS card number 89-7390. To study electrochemical behaviour of electrode material and its cyclic stability, cyclic voltammetry (CV), galvanostatic charge–discharge (GCD) and electrochemical impedance spectroscopy (EIS) studies was executed. BaO/NiO/rGO possesses 1072 F/g specific capacitance at 0.3 A/g in aqueous 1 M KOH. The electrochemical action of hybrid device was setup and it revealed 224 F/g at 0.3 A/g within the charging potential of 1.6 V. Capacitive retention of 97.6 % was achieved by asymmetric hybrid supercapacitor even after 5000 cycles at 10 A/g, this shows prepared nanocomposite exceptional cyclic stability in energy storage application.

Enhanced energy density of high entropy alloy (Fe‐Co‐Ni‐Cu‐Mn) and green graphene hybrid supercapacitor

AbstractGiven the growing demand for new materials for supercapacitor applications, high entropy alloys (HEAs) are being extensively investigated. They are an efficient alternative to existing energy sources due to their synergistic contribution from individual element. We demonstrate the development of nanostructured HEA (FeCoNiCuMn) as a cathode material with specific capacitance (Cs) of ~388 F g−1 (5 mV s−1). As anode material, green graphene (rice straw biochar) synthesized using pyrolysis shows a maximum Cs of ~560 F g−1 at similar scan rate (5 mV s−1). A hybrid asymmetric liquid state device was assembled using the FeCoNiCuMn nanostructured HEA and green graphene as electrodes. Utilizing the green source, the device provided a high Cs of 83.22 F g−1 at 2 A g−1. The specific energy of the device was 33.4 Wh kg−1 and specific power of 1.7 kW kg−1. The electrochemical behavior of each element in the high entropy composition was studied through post X‐ray photoelectron spectroscopy and scanning electron microscopic analysis. The chemical behavior of FeCoNiCuMn is further investigated using DFT studies. The enhanced electrochemical properties and synergistic contribution of each element of the HEA is studied via d‐band theory. The current study can be utilized to develop asymmetric hybrid supercapacitors as environmental friendly energy source.

The construction of an asymmetric hybrid supercapacitor with 2D materials MXene and perovskite

The construction of an asymmetric hybrid supercapacitor with 2D materials MXene and perovskite

NiFe2O4@NiCo2O4 hollow algae-like microspheres enabled by Mott-Schottky for electrochemical energy storage

Designing hybrid structure of transition metal oxides (TMOs) with controlled morphology can adjust the electronic structure and create more kinetics reactions. Herein, a new kind of NiFe2O4@NiCo2O4 nanocomposite was synthesized with one pot hydrothermal route. The unique hollow algae-like microspheres with plenty nanowires and the synergistic effect factors promote high electroactive sites and generate a built-in electric field. The constituted Mott-Schottky heterostructure creates strong interfacial interaction, paves the way for the electrolyte ions diffusion and results high charges transfer abilities by reducing the energy barriers in the heterointerfaces. As cathode material, the NiFe2O4@NiCo2O4 presents satisfactory specific capacity of 996C·g−1 at 0.5 A·g−1 and maintains ultrahigh capacity retention of 81 % at 30 A·g−1 with marvellous stability of only 6 % loss during 20,000 cycles. Interestingly, asymmetric hybrid supercapacitor device based NiFe2O4@NiCo2O4//active carbon (AC) provides tremendous energy density of 117.6 Wh·kg−1 at 438 W·kg−1 power density. What’s more, all-solid-state device offers ultra-low self-discharge process of 9.5 % through 24 h. Therefore, the combination of NiFe2O4@NiCo2O4 to form Mott-Schottky heterojunction was a promising strategy to develop electrode material with high energy storage performance.

Enhancing the Electrochemical Performance of ZnO-Co3O4 and Zn-Co-O Supercapacitor Electrodes Due to the In Situ Electrochemical Etching Process and the Formation of Co3O4 Nanoparticles

Zinc oxide (ZnO) and materials based on it are often used to create battery-type supercapacitor electrodes and are considered as promising materials for hybrid asymmetric supercapacitors. However, when creating such electrodes, it is necessary to take into account the instability and degradation of zinc oxide in aggressive environments with a non-neutral pH. To the best of our knowledge, studies of the changes in the properties of ZnO-containing electrodes in alkaline electrolytes have not been carried out. In this work, changes in the structure and properties of these electrodes under alkaline treatment were investigated using the example of ZnO-containing composites, which are often used for the manufacturing of supercapacitor electrodes. Supercapacitor electrodes made of two materials containing ZnO were studied: (i) a heterogeneous ZnO-Co3O4 system, and (ii) a hexagonal h-Zn-Co-O solid solution. A comparison was made between the structure and properties of these materials before and after in situ electrochemical oxidation in the process of measuring cyclic voltammetry and galvanostatic charge/discharge. It has been shown that the structure of both nanoparticles of the heterogeneous ZnO-Co3O4 system and the h-Zn-Co-O solid solution changes due to the dissolution of ZnO in the alkaline electrolyte 3.5 M KOH, with the short-term alkaline treatment producing cobalt and zinc hydroxides, and long-term exposure leading to electrochemical cyclic oxidation–reduction, forming cobalt oxide Co3O4. Since the resulting cobalt oxide nanoparticles are immobilized in the electrode structure, a considerable specific capacity of 446 F g−1 or 74.4 mA h g−1 is achieved at a mass loading of 0.0105 g. The fabricated hybrid capacitor showed a good electrochemical performance, with a series resistance of 0.2 Ohm and a capacitance retention of 87% after 10,000 cycles.

Tweaking the Efficiency of Asymmetric Hybrid Supercapacitors with Mechanochemically Synthesized Mixed‐Metal–Organic Framework‐Derived Metal Oxides

Novel electrode and electrolyte materials are crucial for enhancing supercapacitor efficiency. Metal–organic frameworks (MOFs) have gained attention owing to their high porosity and surface area. However, their low capacity limits their usage. To tackle this, a highly effective mechanochemical annealing strategy is implemented to improve their efficiency. Three different forms of metal oxides NiCo2O4 are derived from bimetallic MOFs by incorporating Ni2+ and Co2+ with linkers 1,3,5‐benzene tricarboxylic acid (MO‐1), 2,6‐naphthalene dicarboxylic acid (MO‐2), and 1,2,4,5‐benzene tetracarboxylic acid (MO‐3). The synthesized metal oxides have different morphologies due to different linkers and displayed remarkable electrochemical performance, attributed to favorable charge transport paths and enhanced electrochemical double‐layer capacitance with an enlarged specific surface area. These metal oxides exhibit specific capacitance values of 913.3, 43.4, and 210 F g−1 at operating voltages of 0.55, 0.55, and 0.6 V for MO‐1, MO‐2, and MO‐3, respectively. Notably, MO‐1 shows extended discharging time and demonstrates the characteristic behavior of battery‐type supercapacitors, making it versatile. The fabricated hybrid supercapacitor (bimetal hybrid supercapacitor) shows pseudocapacitive behavior, reaching up to 1.5 V with a specific capacitance of 65.6 F g−1, energy density of 73.83 W h kg−1, and power density of 1181.2 W kg−1.

All-functionalized-graphene ribbon films for flexible asymmetric supercapacitors with ultrahigh energy and power densities

Asymmetric (hybrid) supercapacitors (ASCs) based on different positive and negative pseudocapacitance materials can deliver more energy density than electric double layer capacitors (EDLCs). Yet, few pseudocapacitive materials can provide high energy and power density, simultaneously, due to their poor conductivity and unfavorable reaction kinetics under fast charge/discharge rates. Here, we graft sulphur- and oxygen- functionalized into interconnected graphene ribbons to improve the accessibility of ion and enhance redox-active sites. The prepared sulphur- and oxygen- functionalized interconnected graphene ribbon (S-IGR and O-IGR) films as positive electrode and negative electrode, respectively, for high energy density flexible ASCs. Benefiting from the more “active sites” for the graphene ribbons, the S-IGR and O-IGR films connect more sulphur and oxygen groups. As a result, the S-IGR and O-IGR films exhibit ultra-high specific capacitance of 1660 F g−1 (1.66 F cm−2) and 428 F g−1 (0.43 F cm−2), respectively. More importantly, the assembled O-IGR//S-IGR ASCs based on aqueous and gel electrolytes exhibit ultra-high energy densities of 106.6 Wh kg−1 and 35.6 Wh kg−1, respectively. With the ultrafast charging and discharging capability, the ASCs based on aqueous electrolytes can be charge/discharged within 0.53 s to deliver high energy density of 15.0 Wh kg−1 and ultrahigh-power density of 101.4 kW kg−1. Thus, this strategy could possibly be used as designing and fabricating new generation of all grphene-based ASCs with high energy and power densities.

Ni/Co-MOFs derived NiS2/Co3S4 heterostructured microspheres for high-performance asymmetric supercapacitors

Despite the relatively mature state with respect to the technology for synthesizing transition metal sulfide structure, preparation of heterostructured transition metal sulfides with superior structure and high specific capacitance is still challenging. Herein, we prepared NiS2/Co3S4 heterostructured microspheres by the two-part hydrothermal method using bimetallic MOFs as precursors. By constructing this heterostructure, we aimed to modify the electronic structure of electrode materials to enhance the electrochemical performance. We did not need carbonization in the preparation process and showed good electrochemical properties with a great appearance. Experimental and characterization analysis demonstrated the successful synthesis of NiS2/Co3S4 heterostructured microspheres. The NiS2/Co3S4 electrode manifests a specific capacity of 252.3 mAh/g at 1 A/g. Furthermore, the hybrid asymmetric supercapacitor with NiS2/Co3S4 as the positive electrode has the energy density of 4.29 Wh kg−1 at the power density of 61.99 W kg−1 according to the stack volume. These heterostructured mixed metal sulfide electrode materials with high specific capacity and high rate provide new ideas for research.

A new streamlined electrochemical assembly procedure to improve conductive polymer-based metal chalcogenide electrodes for innovative energy systems

Reliable, effective, and environmentally friendly supercapacitors still need development despite the progress made in many nanoscale electrode materials. In this area, composite materials made of organic polymers with high electrical conductivity and metal sulfides with various oxidation states were more attractive. This article describes the design and synthesis of zinc sulfide and polyaniline nanocomposites employing a fast and straightforward electrochemical deposition method and their use as electrode materials for supercapacitors. The structural investigation showed clumped spherical for pAni, hexagonal for pure ZnS, and coexisting hexagonal and spherical phases for ZnS@pAni nanocomposites. The ZnS@pAni nanocomposite demonstrated remarkable electrochemical efficiency and faradaic energy storage capabilities with practical reversibility. Also, an impedance inquiry found that the ZnS@pAni composite has better conductivity and a lower charge transfer resistance than its bulk components. ZnS@pAni//AC was used to create a hybrid asymmetric supercapacitor and displayed a large voltage window up to 2.06 V, 235.24 F g−1 specific capacity, and an ultimate energy density of 144.08 Wh kg−1. Also, when energy density drops to 22 Wh kg−1, substantial power delivery is achieved at 6.3 kW kg−1. Moreover, 88.05% of the capacitance was retained after the device completed 5000 cycles, suggesting good ZnS@pAni//AC asymmetric supercapacitor stability.

High performance MnNbS@MXene hybrid electrode for battery-supercapacitor hybrid device and biomedical applications

Hybrid energy storage devices have obtained a lot of interest because of their remarkable capacitance, high stability and multiple applications. The energy-storage capabilities of transition metal sulfides, such as MnNbS, have expanded beyond the domain of oxide-based materials. Transition metal sulfides and the MXene-based nano-architecture materials have been praised because of their synergistically enhanced conductivity and redox flexibility. Manganese niobium sulfide (MnNbS) binary electrode material was synthesized using the hydrothermal method. The MnNbS-MXene nanocomposite electrode was designed to improve the electrochemical characteristics. It exhibited a superior specific capacity (Qs) of 1094 C/g or 1562.85F/g at 1.5 A/g. The hybrid material (MnNbS-MXene) and activated carbon (AC) were used to make the asymmetric hybrid supercapacitors (MNS-MXene//AC). The hybrid device delivered extraordinary Qs of 153.23 C/g, energy density of 35.77 Wh/kg, and power density of 2800 W/kg. To estimate the capacity retention (CR), the device was measured up to 6000 cycles. It also revealed an astonishing CR of 91 %, which is much greater than that of pure MXene//AC and MnNbS//AC. Besides, the MnNbS-MXene//AC nanocomposite electrode is used as a chemical sensor to detect hydrogen peroxide (H2O2). The MnNbS-MXene showed high sensitivity against the H2O2. The device showed the response up to a wide range of H2O2 (1 mM-5mM). Our research presents a perspective and practical application for producing high-performance electrode material based on transition metal sulfide composites and chemical sensors to detect cancerous cells in the body.

RuxV2−xO5 nanowire/templated carbon composite electrodes for supercapacitors

V2O5 nanowires were doped with Ru4+ using a hydrothermal process. RuxV2−xO5 composites were characterized by x-ray diffraction, energy-dispersive x-ray analysis, scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM). The electrochemical performance of the RuxV2−xO5 nanowires/carbon composites were evaluated by cyclic voltammetry and galvanostatic charge-discharge techniques. The RuxV2−xO5/carbon exhibited a maximum specific capacitance of 351 F·g−1 at a scan rate of 5 mV/s in a symmetric coin cell device. The asymmetric hybrid supercapacitor device achieved a specific cell capacitance of 237 F·g−1 at a scan rate of 5 mV/s, which delivers a high energy and power of 74.8 Wh·kg−1 and 5994.5 W·kg−1, respectively.

Utilization of lead-based saturated adsorbents for the fabrication of battery-like hybrid asymmetric supercapacitors

Utilization of lead-based saturated adsorbents for the fabrication of battery-like hybrid asymmetric supercapacitors