Symmetric Supercapacitor Device Research Articles

Morphological impact on the supercapacitive performance of nanostructured ZnO electrodes

This study investigated the influence of the ZnO morphology on the energy storage capacity of symmetric supercapacitor devices, focusing on the defect centers present in the materials due to morpho-structural differences. Thus, ZnOs with five different morphologies were synthesized with varying methods in which the nanoparticles have the form of flowers, bullets, pyramids, hexagons, and rods. All materials were thoroughly characterized by scanning/transmission electron microscopy, X-ray diffraction, and spectroscopic techniques like photoluminescence, UV–Vis, Raman, and electron paramagnetic resonance spectroscopy. Subsequently, the ZnO-based materials were assembled in symmetric supercapacitor devices to test their energy storage capabilities. The ZnO with nanorod and hexagonal morphologies showed the best specific capacity (180 and 142 F/g), energy density (25 and 19 Wh/kg), and power density (211 and 252 kW/kg) values. The importance of the defect centers in the materials was highlighted, where the ratio between the Zn and O vacancies, evidenced by EPR spectroscopy, plays a crucial role in the ZnO materials’ energy storage capacity. The Raman results support the proposed model, which underlines the importance of oxygen vacancies. In contrast, BET measurements show that the specific surface area of the morphologically distinct ZnO materials does not change drastically, validating the importance of the defect centers in the materials. A so-called “bottle-neck” effect is proposed to describe the relation between the paramagnetic vacancies and the electric properties of the materials.

CNT Functionalized GdCoBi Ternary Metal Oxide Nanocomposite for Electrochemical Detection of Perfluorooctanoic Acid and Energy Storage Applications

Perfluorooctanoic acid “Forever Chemical” presents substantial ecological challenges owing to its persistence and resistance to degradation. The study introduces a novel approach by integrating ternary metal oxides—Gd2O3, Co3O4, and Bi2O3 with carbon nanotubes to develop a versatile electrode material, CNT@GdCoBi NCs, which demonstrates dual functionality as both an electrochemical sensor for PFOA and a component for energy storage devices. The electrode exhibits outstanding electrochemical sensing performance, with a detection limit for PFOA of 4.9 ppb. Interference tests reveal the electrode's high selectivity for PFOA, with a tolerance limit of ≤5%. Practical application on various fruits, vegetables, and water samples shows an average relative standard deviation (%RSD) between 4.8 and 5.6%, underscoring the practical effectiveness of the CNT@GdCoBi NCs electrode. Furthermore, the CNT@GdCoBi NCs exhibit remarkable supercapacitor performance, achieving a specific capacitance of 1197F/g at 2A/g, which is 1.5 times higher than that of GdCoBi NCs. At a current density of 2A/g, the symmetric supercapacitor device demonstrates a specific capacitance of 269F/g, along with a high energy density of 52Wh/kg at a power density of 500W/kg. Additionally, the CNT@GdCoBi NCs electrode maintains good durability, retaining 94% of its capacitance after 10,000 cycles.

A facile one-pot synthesis of hierarchical porous carbon for supercapacitor electrodes

This study presents a facile, environmentally friendly approach to fabricate hierarchical porous carbon for supercapacitor electrodes. The one-pot synthesis of PFO/silica/PTFE via co-pyrolysis generates ideal hierarchical porous carbon. Compared with traditional methods, this method eliminates toxic solvents and complex cleaning steps. PPC-2 obtained under the optimized activation time has the highest specific surface area (2657 m2 g−1) and a remarkable total pore volume (2.96 cm3 g−1). These properties result in a remarkable specific capacitance of 335.9–210.8 F g−1 at current densities of 0.5–10 A g−1 in KOH electrolyte. The electrochemical performance of the PPC-2 electrode in a symmetric supercapacitor device was measured in aqueous (6 M KOH) and ionic liquid (EMIM-TFSI) electrolytes. In EMIM-TFSI, PPC-2//PPC-2 provides an energy density of 48.5 Wh/kg even at a power density of 750 W kg−1. This facile one-pot synthesis method offers a sustainable and scalable approach to produce high-performance hierarchical porous carbon for supercapacitor applications.

Y-Shaped Acceptor-π-Donor-π-Acceptor Configured Anthraquinone-Tethered Phenothiazine Molecular Scaffold for High-Performance Organic Pseudocapacitors.

For the first time acceptor-π-donor-π-acceptor (A-π-D-π-A) based Y-type organic electrode material have been designed and successfully utilized in supercapacitor (SC) application. This Y-type molecular architecture coined as AQ-Im-PTZ-Im-AQ based on anthraquinone (AQ) (A)-imidazole (Im) (π)-phenothiazine (PTZ) (D)-imidazole (Im) (π)-anthraquinone (AQ) (A) in combination with graphite foil (GF). As-fabricated PTZ-Im-AQ/GF and AQ-Im-PTZ-Im-AQ/GF electrode have shown the good energy storage properties in three-electrode supercapacitor system. Moreover, two-electrode symmetric supercapacitor (SSC) device based on AQ-Im-PTZ-Im-AQ/GF electrode exhibited specific capacitance (Csp) of 68.97 F g-1 at 1 A g-1 current density. The specific electron density (ED) of SSC was observed to be 12.06 Wh kg-1 at a specific power density (PD) of 1798.50 W kg-1. The SSC device exhibited 81.62 % of Csp retention after 5000 galvanostatic charge-discharge (GCD) cycles. For real world applications, AQ-Im-PTZ-Im-AQ/GF electrode was tested in symmetric Csp coin cell with applied potential voltage window of -0.4 to 1.0 V was found to be 112.32 F g-1 at 0.5 A g-1. Moreover, it realized high specific capacitance and high energy density of 19.66 Wh kg-1 at 891.94 W kg-1 power density. As a results, AQ-Im-PTZ-Im-AQ/GF make as an attractive electrode material for application in next-generation SCs.

Binder-Free Approach of Mixed-Valent Oxovanadates Anchored on MWCNTs as Supercapacitive Electrodes to Symmetric Supercapacitor Devices: Enriched Performance through the Incorporation of Guest Molecules in Capsular-Shaped Polyanions

Binder-Free Approach of Mixed-Valent Oxovanadates Anchored on MWCNTs as Supercapacitive Electrodes to Symmetric Supercapacitor Devices: Enriched Performance through the Incorporation of Guest Molecules in Capsular-Shaped Polyanions

Integration of 2D borophene into semiconducting N, P, S, and F-doped 1D carbon for energy storage and conversion devices

Innovative energy storage and high-performing conversion devices are urgently required to meet global energy issues. In this study, we synthesized and characterized a nitrogen, phosphorus, sulfur, and fluorine-doped one-dimensional carbon (NPSF@C) integrated with two-dimensional borophene (Bph) nanosheets, forming a nanocomposite (NPSF@C/Bph). The physicochemical and structural characterization confirmed borophene’s successful doping and integration into the NPSF@C matrix. Density Functional Theory (DFT) analysis indicated that the doping of heteroatoms and the integration of Bph increased the number of conduction bands in NPSF@C/Bph, effectively reducing the band gap of the material from 1.99 eV (MWCNT) and 1.43 eV (Bph) to 0.067 eV. This transformation was attributed to the introduction of localized states near the Fermi level and an enhanced density of states, resulting in a metal-like behavior for the NPSF@C/Bph composite. The NPSF@C/Bph composite demonstrated a specific surface area of 1962.78 m2/g and a pore volume of 1.2423 cm3/g, significantly enhancing its electrochemical performance. The composite showed a high specific capacitance of 837F/g at a current density of 1 A/g and retained 92.72 % of its initial capacitance after 10,000 cycles. It also exhibited a high energy density of 78.28 Wh/kg and a power density of 4545 W/kg in a symmetric supercapacitor device. Additionally, electrochemical tests revealed that the NPSF@C/Bph composite exhibited a lower overpotential and higher current density for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) compared to its counterparts. Specifically, the overpotential for OER is 283 eV, and HER is 73 mV at a current density of 10 mA/cm2. The Tafel slopes were 63 mV/dec for OER and 67 mV/dec for HER, indicating superior reaction kinetics.

Fluorinated reduced graphene oxide nanosheets for symmetric supercapacitor device performance

This study explores the potential of using spent lithium-ion battery anodes (graphite) for fabricating symmetric energy devices through a simple regeneration process. Specifically, the use of fluorine-doped reduced graphene oxide (RGO) nanosheets derived from waste batteries as the basis for a symmetric supercapacitor (SC) device is investigated. To enhance the electrochemical energy storage capabilities, a facile hydrothermal technique is employed to synthesize fluorinated graphene. Fluorination of the graphene sheets is successfully realized, as confirmed by the presence of boron with a 2.94 at.% fluorine-doped level, according to the Energy dispersive spectroscopy (EDS) spectrum analysis. Electrochemical analysis of the F-RGO electrode performance consistent with electric double-layer capacitance. Moreover, with a three-electrode system, the F-RGO electrode achieves a maximum specific capacitance of 207F/g under a current density of 1 A/g. A two-electrode symmetric device employing F-RGO exhibits a specific capacitance of 54F/g at 1 A/g. Furthermore, electrochemical impedance measurements demonstrate low charge transfer resistance (Rct) values, specifically 8.63 Ω for F-RGO, signifying improved electrochemical performance. Thus, fluorine atomic doping in RGO nanosheets contributes to the improvements of the specific capacitance and overall superior electrochemical performance of F-RGO, and F-RGO is a highly electrochemical active material for high-performance energy storage electrodes for SCs.

Supercapacitor devices based on multiphase MgTiO3 perovskites doped with Mn2+ ions

Recently, perovskites have become a hotspot for researchers attempting to exploit metal and oxygen vacancies in structures of the form MTiO3, facilitating the convenient electron/hole migration, thus displaying interesting properties. Magnesium Titanate (MgTiO3) is a prominent part of the perovskite class, exhibiting remarkable electrical, thermal, and chemical properties. Undoped and Mn-doped MgTiO3 samples were obtained using a solid-state reaction starting from previously synthesized MgO and TiO2 powders, which were separately doped with different Mn ion concentrations. The resulting multiphase materials with a major MgTiO3 phase were thoroughly morpho-structurally analyzed employing XRD, STEM, Raman, PL, XPS, and EPR spectroscopy. The electrochemical results indicate that they show superior performance when used as electrode materials for supercapacitor application due to the high defect concentration as shown in EPR and PL spectroscopy and the ferroelectric behavior observed in XPS and XRD. When used in symmetric and asymmetric supercapacitor devices, they show promising results, with specific capacity values reaching up to 109 F/g for the symmetric and 609 F/g for the asymmetric devices, while energy and power density values reached 84.7 Wh/kg and 90.8 kW/kg respectively, proving a great potential in the energy storage field.

Impressive electrochemical characteristics of freeze-dried nanosheet structured Mn2P2O7 for affordable electrochemical capacitor

The electrochemical capacitive performance of supercapacitors (SCs) is mainly evaluated by active electrode material, which plays a critical participation. At present, transitional metallic pyrophosphates (TMPs) have grabbed more interest as active electrodes in SC configuration. In this work scenario, we informed a novel strategic synthesis route for constructing Mn2P2O7 (MP) through an ultrasonic probe-assisted chemical reaction approach. The electrode in the form of a monoclinic, freeze-dried nanosheet structure characterized by XRD, FESEM- TEM, and its signature chemical bonds and chemical composition were confirmed via FTIR and EDS analysis, respectively. As prepared active sample was successfully sent into electrochemical investigation tools such as Cyclic Voltagrams (CV), Galvanostatic charge/discharge (GCD), electrochemical impedance analysis (EIS), and Cycling life span (stability) using three and two-electrode set-up. These tests indicate that the active sample holds an impressive capacitive value of 558 F/g at scanning range of 2 mV/s, a specific capacity of 420 C/g at 1 A g-1, magnificent rate capability, 90 % retention over 10,000 successive voltammograms in three-electrode measurements. Additionally, the fabricated symmetric supercapacitor device shows superior energy density, power density, and good rate capability in two electrode investigations. The mentioned prominent results reflect that engineered MP and its characteristics are the efficient fruits in manufacturing affordable electrochemical capacitors.

Synthesis, fabrication, and performance evaluation of lanthanum doped nickel cobalt ferrite electrode for supercapacitors in energy storage applications

The escalating demand for high-quality energy storage devices has become a paramount concern in the contemporary scenario. Despite the potential of supercapacitors for high-quality energy storage, developing sustainable and improved electrode materials remains a challenge. This work investigates the synthesis and characterization of a novel optimally lanthanum-doped nickel cobalt ferrite, for its potential application in supercapacitors. The synthesized nano ferrite is utilized in a two-electrode system as a symmetrical supercapacitor device. The obtained morphological and electrochemical results of both two and three-electrode systems confirm their suitability for effective deployment in supercapacitor electrodes. A high specific capacitance of 706 F/g and energy density of 152.9 Wh/g is obtained for the fabricated device with a retention capacity of 86 % even after 10,000 cycles. The electrochemical results are also validated using an electrical method. The exploration of this lanthanum-doped nano ferrite is expected to be a suitable candidate for the fabrication of supercapacitor electrodes for augmented energy storage performance.

Nickel doped tungsten disulfide grown on carbon cloth for flexible supercapacitors

We present the synthesis of flower-shaped nickel-doped tungsten disulfide on flexible activated carbon cloth (ACC) using a simple hydrothermal technique for flexible symmetric supercapacitors. The nickel-to-tungsten disulfide doping ratio is optimized by adjusting the mass ratio of nickel and tungsten disulfide (Ni:WS2 = 0.5:3, 1:3, and 1.5:3) to enhance charge storage capability, surface area, impedance behavior, specific capacity, and rate capability. The improved supercapacitor performance is attributed to the increased electrochemically active surface area, reduced impedance, and phase engineering from 2 H to 1 T achieved through optimal nickel doping. At a current density of 1 A g−1, the flexible symmetric supercapacitor device (Ni-WS2-ACC device) demonstrates a specific capacitance of 259.2 F g−1, an energy density of 22.4 Wh kg−1, and a power density of 803 W kg−1. Moreover, the Ni-WS2-ACC device maintains consistent supercapacitive performance under various bending conditions. These results present a promising strategy for further enhancing tungsten disulfide-based flexible supercapacitors as energy storage devices.

An environmentally sustainable ultrasonic-assisted exfoliation approach to graphene and its nanocompositing with polyaniline for supercapacitor applications

In the present work, a green high-yielding method for the preparation of graphene is introduced via ultrasonic-assisted liquid phase exfoliation (LPE) of graphite in a green solvent medium, since the common preparation method of graphene via graphite oxide is hazardous. A high concentration of 3.2 mg/ml graphene is achieved here in a comparatively short duration of 3 h ultrasonication. By using a mixed solvents strategy (acetophenone and isopropyl alcohol, 1:19 V/V), surface energy requirements needed for the exfoliation of graphite are satisfied here with acetophenone, where isopropyl alcohol further facilitated the exfoliation via non-conventional CH-π and OH-π interactions. Turbostratic graphene in high-yield (16 %) in a simple means of ultrasonic assisted LPE is the added attraction of the present procedure. The less-defective structure of graphene, its few-layered turbostratic nature, and edge functionalization of the sheets are evident from the material characterization via Raman spectroscopy, XRD, TEM-SAED, and XPS analyses. Here, we report a combination of the attractive conducting polymer polyaniline (PANI) with the as-prepared graphene for supercapacitor applications, where the PANI/graphene nanocomposites with different aniline concentrations (PANI1.125/G, PANI4.5/G, and PANI9/G) have been prepared via in-situ polymerization of aniline in the graphene dispersion. The structure and morphology of the nanocomposites are investigated using different characterization techniques which revealed that the molecular structure of the PANI is retained in the nanocomposites even with a strong interaction with graphene. FESEM and TEM images revealed the good coverage of graphene sheets with PANI that limit the volume change of PANI during the repeated charge-discharge processes. Electrochemical studies showed that PANI4.5/G has the highest specific capacitance of 126.16 mF/cm2 at a current density of 1 mA/cm2, resulting from the perfect combination of the pseudocapacitance behavior of the PANI along with the electrical double layer capacitance of graphene. A symmetric supercapacitor device is also fabricated with PANI4.5/G, which showed the highest areal capacitance of 116.38 mF/cm2 similar to that with three-electrode studies and also good cycling stability with 87 % capacitance retention in the specific capacitance after 6000 cycles. It also exhibited an energy density of 16 µWh/cm2 (0.29 Wh/kg) and a power density of 3.99 mW/cm2 (72.72 W/kg).

Novel electrochromic-supercapacitor device based on P(TPACz)/WO3-PDA nanocomposite film

Organic–inorganic composites of (E)-3,5-di(9 H-carbazol-9-yl)-N-(4-(diphenylamino)benzylidene)aniline/dopamine-modified WO3 (P(TPACz)/WO3-PDA) were prepared by electrochemical polymerisation. The as-prepared P(TPACz)/WO3-PDA composites showed good electrochromic and electrochemical performance. The prominent electrochemical performance of P(TPACz)/WO3-PDA represents a high areal capacitance (32.15 mF cm−2 at 0.1 mA cm−2) and wide range of potential windows (-2.0−1.6 V). Additionally, symmetric supercapacitor devices based on P(TPACz)/WO3-PDA composite films were successfully constructed, which exhibited a high specific capacitance (13.88 mF cm−2 at 0.02 mA cm−2) and an energy density of 7.71 × 10−3 mWh cm−2 in n-doped station. The remarkable electrochromic and electrochemical performances are due to the synergy between the organic polymer and WO3-PDA. A complete large-area composite film structure with high conductivity promises fast electronic transport. This study provides a method for preparing multifunctional composite electrode materials, offering technical support for intelligent displays and energy storage technologies.

Cornstarch as a green binder in supercapacitors: Understanding the effect of binder on the charge storage mechanism

This study used a scalable process to fabricate activated carbon (AC) supercapacitor electrodes with cornstarch as a green binder. A vital aspect of this study was comparing its performance with synthetic binders like polyvinylidene fluoride (PVDF) and Nafion. The chemical and physical properties of the AC were characterized using Brunauer-Emmett-Teller (BET), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Raman spectroscopy, and Field Emission Scanning Electron Microscopy (FE-SEM). Water contact angle measurements evaluated the hydrophilicity of AC-based electrodes with different binders. Their electrochemical characteristics were studied using open circuit potential (OCP), cyclic voltammetry (CV), galvanic charge/discharge (GCD), and electrochemical impedance spectroscopy (EIS) in 1 M NaSO4 electrolyte, and the charge storage mechanism was discussed in detail. The starch binder significantly facilitated the charge storage mechanism by suppressing diffusion limitations compared to other binders. The fabricated symmetric supercapacitor device of starch-based electrodes exhibited the highest Cs of 120 F/g at a specific current of 1 A g-1 with a high energy density of 135 Wh/kg and an exact power density of 750 W/kg. The starch-based supercapacitor device exhibited a capacitance retention of 104 % and 65.5 % at specific currents of 2 A g-1 and 10 A g-1 after 10,000 cycles of charging/discharging, respectively.

Theoretical and experimental studies on 2D β-NiS battery-type electrodes for high-performance supercapacitor

Recently, quirky features and eccentric structures of transition metal sulfides have grasped great attention to remove roadblocks and unwrap fresh avenues for electrodes in energy storage devices. Herein, we developed a 2D beta phase nickel sulfide nanosheets (2D β-NiS NSs) electrode with remarkable enhancement in charge storage properties. When served as active electrodes for electrochemical tests, 2D NiS NSs exhibited ultra-high capacitance of 2693 Fg−1 at 1 mVs−1 and specific capacity of 219 mAhg−1 at 1 Ag−1. The symmetric battery type solid-state supercapacitor device comprising 2D β-NiS NSs electrodes exhibits specific capacity of 83.43 mAhg−1at 2 Ag−1 over broad potential range of 0.7V with good cycling performance, and energy and power density of 28.9 Whkg−1 (@ 2 Ag−1) and 21 kWkg−1 (@ 6 Ag−1) respectively. Complementary first-principles density functional theory (DFT) calculations accomplished to explore the electrolyte ion interactions with nickel sulfide nanostructures defining 2D NiS NSs as a potential candidate for real-time applications.

Morphologically tuned MnO2 thin film electrodes prepared by growth kinetic dependent SILAR approach for high-performance extrinsic pseudocapacitors

Rationally designed electrode materials that are morphologically tuned to attain large surface area can significantly possess the extrinsic pseudocapacitive charge-storing ability. Therefore, the current work approach focuses on synthesizing binder-free MnO2 thin film electrodes with tuned morphology by the SILAR method through alteration in growth kinetics. The growth kinetics of SILAR are controlled by altering the precursor concentrations ratio among metal precursor (MnCl2) and oxidizing agent (KMnO4). The structural analysis confirmed the preparation of the δ-MnO2 phase of manganese oxide. Moreover, alteration in growth kinetics resulted in a change in surface morphology with reduced nanowire size of marigold-like δ-MnO2 microflowers. The MO-3 thin film electrode prepared at an optimum KMnO4 and MnCl2 precursor concentration ratio of 2:1 provides the maximum extrinsic pseudocapacitive conduct with the maximum specific capacitance of 774.5 F g−1. Furthermore, the aqueous symmetric supercapacitor device exhibits the highest specific capacitance of 106 F g−1 with a specific energy of 14.8 Wh kg−1 at a high specific power of 1792 W kg−1 and exhibits 83.2 % capacitive retention over 10,000 cycles. Furthermore, the symmetric aqueous device (MO-3//Na2SO4//MO-3) lights 5 red LEDs, demonstrating its commercial viability for energy storage systems. This research facilitated the scalable synthesis of binder-free δ-MnO2 fine film electrodes with a desired morphology by facile SILAR method, ensuring their practical applicability in symmetric extrinsic pseudocapacitor devices.

Bulk scale synthesis of high-performance carbon nanomaterial from biogas plant residual waste: Tuned porosity and composition for advanced supercapacitor applications

Carbon based nanomaterials with tuned porosity and compositions are of great interest in terms of energy storing materials. Nevertheless, it is still a challenge to produce such nanostructures on a large scale in cost-effective manner. In this work, we demonstrate that carbon nanomaterial (CNM) can be prepared using biogas plant residual waste (BPRW) as the precursor on a bulk scale under the specific two step pyrolysis technique. The optimized process along with the catalyst used is crucial as the simple pyrolysis of precursor can only produce traditional activated carbon with significantly lower specific capacitance values. The spherical structure of silica nanoclusters and graphitic skeleton of synthesized CNM confirmed with the help of FE-SEM, AFM and HR-TEM along with Raman and XRD while EDX, XPS, and FT-IR studies confirm the presence of various functional groups along with their respective percentage composition. These CNMs show mesoporous structure of the nanomaterial. Among three different aqueous electrolytes, the maximum specific capacitance of 371.88 Fg−1 at 0.5 Ag−1 current density in 1 M H2SO4 indicates its suitability for the practical supercapacitor applications. The fabricated symmetric supercapacitor device using CNMs as the electrode material and 1 M H2SO4 as the electrolyte shows very good specific capacitance value with the high energy density of 34.4 Whkg−1 corresponding to 360 Wkg−1 power density along with the good cyclic stability over 10,000 cycles of charge–discharge. This innovative technique paves the way towards upcycling any lignin containing waste material into carbon-based nanomaterial on a bulk scale by an effective method, which can be further used as high-performance electrode material for energy storage applications like in supercapacitors and batteries.

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.

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.

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.