Excellent Specific Capacitance Research Articles

Se as Eutectic Accelerator SPAN Cathode for K−S Batteries with Improved Specific Capacity and Reaction Kinetics

AbstractPotassium‐sulfur (K−S) batteries are regarded as the most promising energy storage applications due to its excellent specific capacity, widespread resources and low‐cost of potassium and sulfur. As a cathode material, the unique solid‐solid reaction mechanism of sulfurized poly(acrylonitrile) (SPAN) effectively restrains the shuttle effect and closes to 100 % for coulombic efficiency. However, the application of SPAN is still limited by its sluggish kinetics and inferior cycle performance. Herein, a SPAN with Se as eutectic accelerator (Se‐SPAN) was synthesized via vacuum melting and sulfurization treatments, Se not only enhances the reaction kinetics of S but also improves utilization rate of S. Compared to SPAN, the Se‐SPAN shows outstanding capacity of 1551 mAh g−1 at 0.1 C and 1311.3 mAh g−1 at 0.5 C. In addition, a superior cycle stability is acquired with a capacity retention of 87.4 % at 0.5 C for 100 cycles. Therefore, this work provides a strategy to design high performance electrode materials for K−S batteries.

Effect of reducing agents on structural, morphological, optical and electrochemical properties of Mn2O3 nanoparticles by co-precipitation method

Abstract In this work, two different reducing agents namely sodium hydroxide and potassium hydroxide (NaOH and KMnO4) were used to synthesis of manganese oxide (Mn2O3) nanoparticles by the co-precipitation method and examined for the electrochemical applications. The as-prepared Mn2O3 nanoparticles using NaOH precursor, dried in a hot oven at 80 °C for 6 h (MN-1) and then annealed for 7 h at 600 °C (MN-2). Similarly, Mn2O3 nanoparticles were prepared using KMnO4 precursor, dried in a hot oven at 80 °C for 6 h (MK-1) and then annealed for 7 h at 450 °C (MK-2), respectively. The influences of reducing agents on structural, morphological and optical properties were investigated. The structural analysis revealed the prepared samples had tetragonal crystal structures with better crystallinity. FT-IR spectral analysis revealed the characteristic bonds of Mn–O–Mn were observed in the region of 486–573 cm−1. The FE-SEM and HR-TEM images showed coral-like and nanorod structures for samples MN-2 and MK-2, with exhibited lattice value of 0.27 nm related to the (222) plane. The presence of the elements manganese (Mn) and oxygen (O) was confirmed by EDAX mapping. The XPS study confirmed that the oxidation state of the prepared samples was +2. The UV-Vis spectra suggested that the adsorption edge was blue-shifted compared to the sample MN-2. Cyclic voltammetry (CV) and galvanostatic charge–discharge experiments demonstrated that charge storage in Mn2O3 exhibited faradic-dominated capacitive behavior. MN-2 nanorod structures were obtained at excellent specific capacitance value of 196 F g−1 compared to MK-2 nanoparticles. Based on this study, Mn2O3 nanoparticles was recommended as exceptional electrode materials for efficient supercapacitor applications due to its superior electrical conductivity, large surface area and redox properties.

Flexible low-temperature zinc ion supercapacitor based on gel electrolyte with α-MnO2@rGO electrode

Zinc ion supercapacitors (ZSCs) are considered to be a new generation of energy storage device because of their low cost and battery-like performance. However, the uncontrollable structural deformation and poor cyclic stability make them a great challenge in practical applications. Herein, we developed a flexible quasi-solid-state ZSC assembled with gel electrolytes, porous α-MnO2@reduced graphene oxide(α-MnO2@rGO) cathode, and activated carbon/carbon cloth (AC/CC) anode. The gel electrolytes containing polyvinyl alcohol (PVA), carboxymethylcellulose (CMC), and ethylene glycol (EG) shows great mechanical properties, good electrical conductivity, and can afford a wide electrochemical potential window. The flexible ZSC exhibited an excellent specific capacitance of 575.5 mF cm−2 at a current density of 6 mA cm−2 and good stability during bending test. More important, the device can achieve stable electrochemical properties at low temperature of −20 °C, cycle retention can maintain 89.189 % even after 5000 cycles. This work has successfully proposed an energy storage system with excellent performance, which provides possibilities for multi-scene applications of flexible devices.

Ni2CoS4@(NiCo)Se2 bimetallic selenides with core–shell heterostructure in-situ generated on Ni2CoS4 nanorods arrays for high performance supercapacitors

In this paper, Ni2CoS4@(NiCo)Se2/NF core–shell structural nanocomposites are successfully prepared on nickel foam (NF) substrates through a convenient hydrothermal method and tube furnace calcination. Firstly, NiCo2O4/NF is acquired by a one-step simple hydrothermal method and one-step tube furnace calcination, then it is sulfidated via a one-step hydrothermal method, and finally selenized by stirring to obtain Ni2CoS4@(NiCo)Se2/NF. The results show that in the three-electrode test, the specific capacitance of the Ni2CoS4@(NiCo)Se2 electrode is able to reach 6054 mF·cm−2 at a current density of 10 mA·cm−2. The excellent performance of Ni2CoS4@(NiCo)Se2/NF nanocomposites is supposed to give rise to the bimetallic synergistic effect, as well as the unique core–shell structure of its surface-loaded nanosheets. In addition, all-solid-state asymmetric supercapacitors (ASCs) are composed of activated carbon (AC) as the anode and Ni2CoS4@(NiCo)Se2/NF as the cathode. The prepared Ni2CoS4@(NiCo)Se2/NF//AC ASC devices reach an energy density of 53 Wh kg−1 at a power density of 480 W kg−1. Simultaneously, Ni2CoS4@(NiCo)Se2/NF//AC ASC device has an excellent specific capacitance of 149.06F g−1 at a current density of 0.6 A/g and a capacitance retention rate of 84.0 % after 10,000 electrochemical cycles, which proves its good cycling stability. Impressively, two Ni2CoS4@(NiCo)Se2/NF//AC ASC devices connected in series can light up a 2.5 V LED lamp and continue to illuminate it for 11 min. Our results show that Ni2CoS4@(NiCo)Se2/NF nanocomposites with core–shell structures have great application potential in energy storage devices.

Facile production of Ag-Co3O4/rGO nanocomposite and its enhanced photocatalytic and electrochemical activities for practical applications

In this study, authors produced Co3O4, Ag-Co3O4 nanoparticles and Ag-Co3O4/rGO nanocomposites through a facile, one-step and cost-effective hydrothermal route; and thoroughly analyzed these materials using a variety of complementary techniques, including XRD, SEM/TEM, XPS, FTIR, VSM, UV–Vis, PL, photocatalytic and electrochemical measurements. The formation of cubic spinel structure in Ag-Co3O4/rGO nanocomposite was investigated by X-ray diffraction. The estimated average crystalline size in case ofCo3O4, Ag-Co3O4, and Ag-Co3O4/rGO samples was found to be 11.2, 14.1 and 17.5 nm, respectively. As a comparison to Co3O4 and Ag-Co3O4 nanoparticles, the absorption edge of Ag-Co3O4/rGO nanocomposite was significantly shifted towards the visible region, and hence the band gap is narrowed due to highly conducting Ag and rGO incorporation. The photo-generated electrons and holes were rapidly transferred from Co3O4 to Ag and rGO, leading to reduced PL intensity ofAg-Co3O4/rGO nanocomposite. Authors evaluated the photocatalytic efficiency of synthesized Ag-Co3O4/rGO nanocomposite, which exhibited an enhanced photodegradation potential against RhB dye. Authors also examined the electrochemical activity of as-obtained Ag-Co3O4/rGO nanocomposite using cyclic voltammetry and galvanostatic charge-discharge cycle analysis, demonstrating its employability in supercapacitors as it possessed excellent specific capacitance.

Manufacturing woven carbon fabrics with electrode function via high-pressure spray of active lithium-ion particles

In this paper, an innovative approach was presented to manufacture woven carbon fabric cathodes via high-pressure spray to coat LiFePO4 (LFP), acetylene black (AB) and polyvinylidene fluoride (PVDF) onto carbon fibers. The fabrics were desized to improve conductivity prior to coating. Fourier-transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were adopted to ensure that the selected process parameters could achieve complete removal of the polymer sizing and dispersion of the LFP particles on both the spray surface and inner architecture of the fabrics. The subsequent electrochemical characterization showed that the fabric cathodes could, on average, produce excellent specific capacities of over 110 mAh/g and areal capacities of over 3.0 mAh/cm2 with good rate performance. With 98% efficiency and 0.97 retention after 100 cycles, the cathodes also depicted superb long-cycle performance, meaning that the coating with electrochemical activity could adhere firmly to the fiber surface.

Biomass-based porous carbon from trachycarpus fortunei silk with the hierarchical oxygen-enriched structure for high performance flexible all-solid-state supercapacitor

Hierarchical porous carbons with diverse pore scales are commonly chosen as electrode materials for high-performance supercapacitors due to their excellent electrochemical properties. Herein, a novel synthetic method, dilute H2SO4 pretreatment coupling with subsequent KOH activation, is adopted to prepare hierarchical oxygen-enriched porous carbon using trachycarpus fortunei silk (TFSPC) waste as the raw material. The optimized TFSPC2 possesses a 2049 m2 g−1 specific surface area, 1.58 cm3 g−1 total pore volume, and 22.54 at% oxygen-containing doping. Benefiting from such characteristics, the TFSPC2 electrode exhibits an excellent specific capacitance of 469 F g−1 at 0.5 A g−1 and remarkable cycling stability of only 4.94% capacitance decay even after 20000 uninterrupted cycles in a 6 M KOH electrolyte. Furthermore, the assembled flexible symmetric supercapacitor device TFSPC2//TFSPC2 achieves a high energy density of 14.60 Wh kg−1 in a potential range of 0–1.3 V when the power density is 320 W kg−1. More importantly, the TFSPC2//TFSPC2 device demonstrates superior mechanical flexibility and maintains 88.70% capacity retention even through 2000 cycles (90°) of reduplicative bending/recovering. The research provides a low-cost, green, and renewable strategy for the synthesis of hierarchical porous carbons for supercapacitors.

A rigid-flexible gel polymer electrolytes with long cycle life and dendrite-free in lithium metal batteries

Gel polymer electrolytes (GPEs) in lithium-ion batteries (LIBs) are promising alternatives to liquid electrolytes due to their higher safety and energy density. However, GPE suffers from low ionic conductivity and poor interfacial compatibility. Here, we demonstrate a rigid-flexible GPE (CPE(PVAc)) of the PVDF-HFP/LAGP/PVAc/LiTFSI was prepared by a simple solution casting method. A fast route and efficient for the transport of lithium ions had been constructed by dripping a small amount of LEF (1 M LiTFSI/EC-DMC-FEC (1:1:0.2 v/v/v)) on both sides of the membrane. Moreover, a stable LiF-rich SEI layer was formed on the Li anode, effectively inhibited the growth of lithium dendrites. The CPE(PVAc) possesses high ionic conductivity (1.47 mS cm−1 at 30 °C) and robust mechanical properties (230 % fracture length and 3.4 MPa fracture strength). The Li-symmetric cell with CPE(PVAc) can operate for >1500 h of stable operation at 0.1 mA cm−2 and 25 °C. The assembled LiFePO4|CPE(PVAc)|Li coin cells presented excellent initial discharge specific capacity (135.4 mAh g−1 at 2C and 25 °C, and 157.5 mAh g−1 at 1C and 55 °C) and long-term cycling stability (97.6 % capacity retention after 500 cycles at 2C and 25 °C, and 80 % capacity retention after 400 cycles at 1C and 55 °C). The advantages of CPE(PVAc) electrolyte have shown great potential for application in high-performance lithium metal batteries.

Tungsten doping role in structural modification and boosting electrochemical efficiency of Co(OH)2 dandelion assemblies

Globally increasing energy demands and the drastic climate changes are pursuing cost-effective and environmental friendly energy storage option i.e. supercapacitors. Tungsten (W) doping in Co(OH)2 has played an effective role in morphology changes along with improving its super capacitive properties. The 5 % W-doped Co(OH)2 revealed perfectly dandelion assemblies having size range 3–4 µm and emerging wires with ∼10 nm diameter. These dandelion assemblies exhibited pseudocapacitive behavior and excellent specific capacitance 1000 Fg−1 at 1Ag−1 and 1051 Fg−1 at 5mVs−1 which is more than twice as compared to pristine Co(OH)2. Power law (b = 0.71) exhibited capacitive nature of 5 % W-doped Co(OH)2. High cyclic stability with 92 % charge retention have been achieved for 5000 cycles. This improved electrochemical performance is attributed to the high surface area with numerous active sites, amazing Faradaic redox reactions and excellent charge transfer rate. Hence, 5 % W-Co(OH)2 dandelion assemblies are promising electrode materials for efficient supercapacitors.

Carbon nanosheet with controlled porous and disorganized structures as high-rate anode for high-energy Na-ion hybrid capacitors

Although sodium-ion capacitors (SICs) hold great application potential in the areas where energy and power output are both highly required, they still encounter the challenge to design suitable anode materials with quick dynamics to provide high power output. In present work, a ultra-thin porous carbon nanosheet (PCS) combing the structure advantages of soft carbon (ordered nature) and hard carbon (amorphous nature) was successfully designed, which facilitates the charge transport and Na+ migration and thus guarantees the high-rate capacity and long cycle life of PCS electrodes. When tested as anode for sodium-ion batteries (SIBs), the PCS can exhibit an impressive sodium storage performance, including an excellent specific capacity of 302 mAhg−1, a high-rate capacity and a superior cycling stability (85 % capacity retention after 500 cycles at 1C). Furthermore, SICs constructed by PCS can provide a maximum energy density of 158.2 Wh kg−1 and a maximum power density of 22.8 kW kg−1, together with superior cycle lifespan. The excellent electrochemical performance demonstrates that PCS is a prospective electrode material for sodium-ion storage.

Preparation and theoretical analysis of NiCo2O4: xS series materials for high-performance supercapacitors

Nickel cobalt oxide and sulfide electrode materials with various nanostructures were synthesized via a facile hydrothermal method. The structural, morphological, electrochemical, and electronic properties of the electrode materials were studied to evaluate the effect of S addition into NiCo2O4. The results indicated that S atoms can influence the lattice structure and morphology, and appear to improve the electrochemical performance of the material. Excellent specific capacitance and cycling stability were found in the samples. The NiCo2S4 sample exhibited the highest specific capacitance of 1302 F/g at a current density of 1 A/g and a capacity retention of 92.4% after 5000 charge–discharge cycles. First-principles calculations were performed to provide more insight into the mechanism of improved electrochemical performance when S atoms were added to NiCo2O4 and demonstrate their potential as excellent electrode materials. In the NiCo2O4:xS series materials, the addition of S effectively manipulates the surface morphology and interfacial charge states of the materials to achieve superior electrochemical performance.

Pre-Oxidation Strategy Transforming Waste Foam to Hard Carbon Anodes for Boosting Sodium Storage Performance.

Large reserves, high capacity, and low cost are the core competitiveness of disordered carbon materials as excellent anode materials for sodium-ion batteries (SIBs). And the existence and improper treatment of a large number of organic solid wastes will aggravate the burden on the environment, therefore, it is significant to transform wastes into carbon-based materials for sustainable energy utilization. Herein, a kind of hard carbon materials are reported with waste biomass-foam as the precursor, which can improve the sodium storage performance through pre-oxidation strategy. The introduction of oxygen-containing groups can promote structural cross-linking, and inhibit the melting and rearrangement of carbon structure during high-temperature carbonization that produces a disordered structure with a suitable degree of graphitization. Moreover, the micropore structure are also regulated during the high-temperature carbonization process, which is conducive to the storage of sodium ions in the low-voltage plateau region. The optimized sample as an electrode material exhibits excellent reversible specific capacity (308.0mAhg-1) and initial Coulombic efficiency (ICE, 90.1%). In addition, a full cell with the waste foam-derived hard carbon anode and a Na3V2(PO4)3 cathode is constructed with high ICE and energy density. This work provides an effective strategy to conversion the waste to high-value hard carbon anode for sodium-ion batteries.

Ti3C2 MXene Nanosheets/Vanadium Nitride@Carbon Composite Electrodes for High-Performance Lithium-Ion Batteries

Lithium-ion batteries have delivered outstanding charge storage performance due to their high energy density and low cost and also more specialized energy conversion device for next-generation electrical appliances. Herein, we offered the ultrathin Ti3C2 MXene (titanium carbide) nanosheets/vanadium nitride (VN)@carbon (C) nanocomposites for lithium-ion storage application as a high-capacity anode material. The proposed anode material is Ti3C2 MXene nanosheets/VN@C composite as synthesized via chemical precipitation. The real-time half-cell of Ti3C2 MXene nanosheets/VN@C composite shows the excellent initial discharge specific capacity of 1237 mAh g-1 at a current density of 0.1 A g-1 with a reverse rate capacity of 685 mAh g-1. The high specific capacity of 645 mAh g-1 has been attained even after 500 cycles at a current density of 0.1 A g-1. This type of rich reverse rate capacity and stability of the anode electrode is responsible due to the high conductivities and surface areas of Ti3C2 MXene nanosheets/VN@C composite, which is provided easy accessibility of Li+ ions.

Hierarchically fabricated nano flakes-rod-like CoMoO–S supported Ni-foam for high-performance supercapacitor electrode material

Nano-sized CoMoO has emerged as a gifted contender for renewable energy conversion storage applications. However, the limited stability and unique surface areas of oxide-based materials present challenges in the use of supercapacitors (SCs). In this work, we employed a facile hydrothermal method to hierarchically fabricate nanoflakes-rod-like CoMoO–S materials on nickel foam (NF). The resulting electrodes exhibited remarkable electrochemical activity, attributed to the synergistic properties of the well-allied CoMoO 2D nanorods. Notably, the developed CoMoO–S nanoflakes-rod (3D-2D) composites proved an excellent specific capacitance of 1087 F g−1 at 2 A/g current density, along with excellent rate capabilities surpassing those of single CoMoO nanorods electrodes. Furthermore, the CoMoO–S nanoflakes-rod composites exhibited notable cyclic stability, with a retention rate of 86.3 % above 5000 cycles. The exceptional electrochemical characteristics displayed by electrode materials typically used in batteries provide a hopeful strategy for the advancement of high-performance supercapacitors.

Electrochemical performance of asymmetric supercapacitors based on NiCo(OH)4/Cu2(OH)3NO3 electrode

Copper salt metal compounds are widely used in the field of supercapacitor electrode material due to their rich ionic groups. In this paper, NiCo(OH)4/Cu2(OH)3NO3 electrode material is prepared by the solvothermal method by doping NiCo-based hydroxide with copper salt metal compounds (Cu2(OH)3NO3). NiCo(OH)4/Cu2(OH)3NO3 electrode material with different morphologies and sizes is prepared by adjusting the concentration of metal salts. When the metal salt concentration is 2 M, the prepared circular sheet NiCo(OH)4/Cu2(OH)3NO3 electrode material with a diameter of 3 μm and a thickness of 150 nm exhibits excellent specific capacitance (1335 C g−1 at 1 A g−1) and capacitance retention (after 5000 cycles, the capacitance retention rate is 71.7 %). Furthermore, the NiCo(OH)4/Cu2(OH)3NO3//AC asymmetric supercapacitor is prepared, which exhibited an energy density is 83.78 Wh kg−1 at a power density of 800 W kg−1. The capacitance retention rate of the asymmetric supercapacitor is 65.2 % (after 5000 cycles at 10 A g−1). We used copper salt metal compounds (Cu2(OH)3NO3) to improve the electrochemical performance of NiCo-based hydroxide electrode material. This idea has certain reference significance for improving the performance of NiCo-based hydroxide electrode material.

Molybdenum‐Incorporated O3‐type Sodium Layered Oxide Cathodes for High‐Performance Sodium‐Ion Batteries

Transition metal layered oxide materials with a general formula NaxMO2 (M = Ni, Mn, Co, Fe) are widely researched with various possible electrode configurations. Herein, O3‐type NaNi(1−x)/2Mn(1−x)/2MoxO2 (x = 0, 0.05,0.1) layered oxide cathode materials are synthesized by solid‐state reaction method, and its structural, thermal, and electrochemical performance in sodium ion battery is investigated. The structural analysis reveals that a single phase highly crystalline O3‐type cathode material with an irregular particle shape is formed. The introduction of molybdenum improves the thermal stability of cathode materials, which can be attributed to the improved TMO2 layers that provide stability to the material. The addition of Mo to Na‐layered oxide cathode materials enhances electrochemical performance. The developed cathode materials, the NaNi0.475Mn0.475Mo0.05O2, exhibit excellent specific discharge capacity (≈154 mAh g−1) at C/20 rate, (an increase of ≈20% when compared to the NaNi0.5Mn0.5O2) which can be attributed to the increased capacitance effect by the addition of Mo. The electrochemical impedance spectroscopy study reveals that the diffusion of Na+ into/from the host structure is rapid during the first cycle and then gradually reduces with subsequent cycling due to the formation of the solid electrolyte interface layer, which hinders Na+ migration. This has a potential effect on the improved electrochemical performance of the material.

Anhydride-Based Compound with Tunable Redox Properties as Advanced Organic Cathodes for High-Performance Aqueous Zinc-Ion Batteries.

Organic materials with multiple active sites and flexible structural designs are becoming popular for use in aqueous zinc-ion batteries (AZIBs). However, their applicability is limited due to the low specific capacity and poor cycle stability originating from the introduction of inactive units and high solubility. Herein, three organic molecules with tunable redox properties were synthesized using anhydride (PMDA, 1,2,4,5-benzenetetracarboxylic anhydride-1,2-diaminoanthraquinone, NTCDA, 1,4,5,8-naphthalenetetracarboxylic dianhydride-1,2-diaminoanthraquinone, and PTCDA, 3,4,9,10-perylenetetracarboxylic dianhydride-1,2-diaminoanthraquinone, referred to as PM12, NT12, and PT12) in the solid-phase method. Density functional theory (DFT) simulations and experiments identified that NT12 exhibits superior electrochemical performance compared with PM12 and PT12 because of the low energy gap and large aromatic conjugated structure. They demonstrated specific capacities of 106.7, 192.9, and 124.9 mA h g-1 at 0.05 A g-1, respectively. Especially, NT12 displayed excellent initial specific capacity (85.4 mA h g-1 at 1 A g-1) and remarkable capacity retention (64.1% for 3000 cycles) due to dual active centers (C═N and C═O). The all-NT12 full-cell also had excellent performance (127.1 mA h g-1 under 1 A g-1 and 80.6% over 200 cycles). The organic compounds synthesized in this work have potential applications of AZIBs, highlighting the importance of molecular design to develop the next generation of advanced materials.

Solvent triggering assembly of self-supported MXene hydrogel for high performance asymmetric supercapacitors

Constructing 3D porous structure of MXene (Ti3C2Tx) is an efficient approach to prevent nanosheets restacking and realize prominent electrochemical functionality. However, the assembly of self-supported 3D Ti3C2Tx architecture is difficult due to the inherent rigidity and superior hydrophilicity of Ti3C2Tx nanosheets. Herein, a solvent-triggering gelation strategy is developed using polar aprotic N,N-Dimethylformamide and polar protic H2O as co-solvent to enhance hydrogen bonding and Ti-O-Ti covalent bonding between Ti3C2Tx nanosheets. Thereby, self-supported Ti3C2Tx hydrogel (MH12/5:5) in absence of any crosslinkers or substrates has been successfully fabricated. The MH12/5:5 hydrogel exhibits excellent specific capacitance of 384.4 F g1 and superb rate capability of 61 % in a broad current density range of 1–100 A g−1. Asymmetric supercapacitor has been assembled using MH12/5:5 hydrogel as negative electrode and a polyaniline hydrogel as positive electrode, which presents high energy density of 21.2 Wh kg−1. This solvent-triggering gelation strategy points toward a promising direction to develop self-supported MXene hydrogels for high performance energy storage devices.

Exceptionally stable electrochemical supercapacitor devices based on V2O5@MnO2 nanocomposite functional anode materials

The performance of supercapacitor devices is mainly limited by the ability to identify anode materials with fair stability and activity. Herein, we demonstrate the efficient synthesis of V2O5@MnO2 nanocomposites. The XRD, XPS, EDS, FESEM, and N2-physisorption techniques are carried out to clarify the crystallinity, elemental composition, morphology, and surface structure associated with the V2O5@MnO2 nanocomposites. Upon use as negative electrodes in supercapacitor devices, the fabricated V2O5@MnO2 nanocomposite displayed excellent specific capacitance over an outstanding operating voltage window (0 to -1 V). Moreover, the constructed symmetric supercapacitor (V2O5@MnO2//V2O5@MnO2) device revealed ultrahigh specific energy (Es) of 69 Wh kg−1 with 1200 W kg−1 under 1.5 A g–1, and an exceptional cell potential of 1.6 V (almost equal to that of an asymmetric device) with remarkable cycling stability. The device retains an exceptional efficiency (∼100 %) over 32,000 consecutive galvanostatic charging/discharging (GCD) cycles. These findings demonstrate the ability of the synthesized nanocomposite for use as viable negative/positive material for high performance devices.

Co-sputtered V2O5–TiN composite on Ag-network current collector for high-performance flexible transparent thin-film supercapacitors

Next-generation wearables require extremely capable electrochemical energy-storage devices that exhibit improved performance with high flexibility and transparency. Herein, we present a highly flexible and transparent electrochemical thin-film supercapacitor electrode fabricated by co-sputtering V2O5 and TiN on an Ag-network-based current collector. The electrodes' physical properties, optical properties, and structural morphologies are studied using X-ray diffraction, UV–visible spectroscopy, and scanning electron microscopy, respectively. A symmetric device is fabricated using V2O5 and TiN on an Ag network, and the TiN sputter power is varied to optimize the performance. The device performance of the co-sputtered electrodes at various composition ratios is studied. The optimized V2O5–TiN (200−40)/Ag electrode device with pseudocapacitive behavior delivers an excellent areal specific capacitance of 98.66 mF cm–2 at a current density of 4 mA cm–2 with a charge retention of 90.12 % after 6000 cycles. The V2O5–TiN (200−40)/Ag electrode device outperforms other reported electrodes, with an energy density and power density of 30.83 μWh cm–2 and 2999.67 μW cm–2, respectively, and excellent mechanical stability.