Synthesis Of Electrode Materials Research Articles

Microwave construction of the 3D porous interconnected structure of NiCoCr medium-entropy alloy with ultra-high specific capacity for supercapacitors and electrocatalysis

The effective design of bifunctional electrodes with unique morphology and remarkable electrochemical properties for energy conversion and storage devices is a promising but challenging endeavor. Herein, self-supporting NiCoCr medium-entropy alloy (MEA) with a hierarchical porous network structure was in situ synthesized on nickel foam (NiCoCr/NF) by a simple and rapid microwave route. The optimal NiCoCr/NF presented an ultra-high specific capacity of 3011.8 C g−1 (1 A g−1) and outstanding charge/discharge sustainability (83.4% retention at 10 A g−1 over 50,000 cycles) due to its multi-component synergistic effect and hierarchical porous structure. Meanwhile, subtle lattice distortions and electron density redistribution in the NiCoCr MEA tuned electronic structures, resulting in a low overpotential and Tafel slope. Aqueous and solid-state asymmetric supercapacitors were fabricated by using NiCoCr/NF as a cathode and Bi/NF as an anode. The aqueous supercapacitor displayed an exceptional energy density of 314.4 Wh kg−1 at a power density of 800 W kg−1 with 81.8% retention at 10 A g−1 over 20,000 cycles. This study provides a new strategy for the efficient synthesis of electrode materials with interconnected network structures and paves the way for the broader application based on medium-entropy and high-entropy materials as promising candidates for future energy storage devices.

Enhancement in photocatalytic and electrochemical performance of hydrothermally synthesized β-Bi2O3 via Ni incorporation

β-Bi2O3 and Ni-incorporated β-Bi2O3 nanoparticles with different Ni incorporating amounts (0, 2, and 4 at. wt. %) were successfully synthesized through a viable hydrothermal process. As-synthesized nanoparticles were analyzed by complementary analytical tools such as X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectroscopy (EDS), UV–visible spectroscopy (UV–Vis), and photoluminescence spectroscopy (PL) for structural, microstructural, compositional, and spectral properties. The photocatalytic performance of synthesized nanoparticles was assessed by subjecting them to visible light irradiation and monitoring the decomposition of rhodamine-B dye. The findings demonstrated that the inclusion of Ni(4%) in β-Bi2O3 nanoparticles significantly enhanced its photocatalytic activity compared to pristine β-Bi2O3 which is desirable for environmental remediation. This improvement may be caused by increased generation of electron-hole (e−-h+) pairs, reduced recombination rate of these pairs, enhanced absorption of visible light, and a decreased band gap energy. To evaluate the specific capacitance characteristics of synthesized electrode materials, cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance analyses were conducted. The super capacitance activities of prepared electrode materials were observed in the order of Bi2O3 < Ni(2%)-Bi2O3 < Ni(4%)-Bi2O3. Notably, Ni(4%)-Bi2O3 nanocomposite exhibited higher supercapacitance, which can be attributed to the effective role of appropriate nickel incorporation in Bi2O3. These results suggested that the incorporation of Ni(4%) into β-Bi2O3 to form a nanocomposite showed greater capability as an effective electrode material for advanced energy storage devices, especially supercapacitors.

MOP-18-Derived CuO Fiber for Hybrid Supercapacitor Electrodes.

This study explores a simple method of fabricating hybrid supercapacitor electrodes, which could potentially broaden the application of this technology. The method involves electrospinning a uniform solution of Matrimid/Metal-Organic Polyhedra 18 (MOP-18) followed by carbonization at a relatively low temperature of 700 °C in air, rather than in an inert atmosphere, to create free-standing, redox-active hybrid supercapacitor electrodes. Additionally, the synthesis procedure requires no stabilization or activation steps, which enhances the cost effectiveness of the synthesized electrode materials. The resulting C/CuO composite was used as the working electrode, with a polyacrylonitrile (PAN)/Poly(methyl methacrylate) (PMMA) carbon nanofiber (CNF) electrode as the counter and 6 M KOH as the electrolyte in a T-cell configuration. The cell performance and redox activity were evaluated using cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS) and cycling stability tests. Additionally, the physical and chemical structures of the electrode materials were assessed using X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron spectroscopy (TEM), X-ray diffractometry (PXRD), surface area analysis and other characterization techniques. The electrode material demonstrated a specific capacitance of up to 206 F/g. Supercapacitors utilizing this material display an energy density of 10.3 Wh/kg (active material) at a current density of 1 A/g in electrochemical testing.

Facile microwave‐assisted hydrothermal synthesis of zinc phosphate nanocrystals as electrode material for high‐rate performance aqueous and non‐aqueous zinc‐ion batteries

AbstractExploring suitable and economically efficient cathode materials for zinc‐ion batteries plays a vital role in combating current challenges and achieving practical applications. Herein, Zn3(PO4)2 nanoparticles with exceptional battery properties were produced via microwave‐assisted hydrothermal synthesis. The synthesis was conducted at different microwave heating times (3, 5, 10, and 15 min) at a fixed temperature of 200°C. The structural properties of synthesized Zn3(PO4)2 were studied via XRD, FESEM‐EDS, and TEM studies, while the electrochemical parameters were evaluated through CV, GCD, and EIS in a standard 3‐electrode system with 1 M KOH as an electrolyte at a room temperature. The electrochemical results show that Zn3(PO4)2 synthesized at 10 min microwave heating time reported the best electrochemical performance with a specific capacity value of 38.90 and 31.89 C/g at a scan rate of 10 mV/s and current density of 1 A/g, respectively. Furthermore, a stability test of the synthesized electrode material reported an excellent cyclability of the electrode with 79% retention of the initial value of its specific capacity after 1000 cycles.

Optimizing Electron Spin-Polarized States of MoSe2 /Cr2 Se3 Heterojunction-Embedded Carbon Nanospheres for Superior Sodium/Potassium-Ion Battery Performances.

The principal challenges faced by sodium-ion batteries (SIBs) and potassium-ion batteries (KIBs) revolve around identifying suitable host materials capable of accommodating metal ions with larger dimensions and addressing the issue of sluggish chemical kinetics. Herein, a MoSe2 /Cr2 Se3 heterojunction uniformly embedded is fabricated in nitrogen-doped hollow carbon nanospheres (MoSe2 /Cr2 Se3 @N-HCSs) as an electrode material for SIBs and KIBs. Cr2 Se3 exhibits spontaneous antiparallel alignment of magnetic moments. Mo2+ doping is employed to regulate the electron spin states of Cr2 Se3 . Moreover, the MoSe2 and Cr2 Se3 heterojunctions induce a lattice mismatch at the heterostructure interface, resulting in spin-polarized states or localized magnetic moments at the interface, potentially contributing to spin-polarized surface capacitance. MoSe2 /Cr2 Se3 @N-HCSs demonstrate a high capacity of 498 mAh g-1 at 0.1 A g-1 with good cycling stability (capacity of 405 mAh g-1 and a coulombic efficiency of 99.8% after 1000 cycles). Additionally, density functional theory (DFT) calculations simulate the accumulation of spin-polarized charges at the MoSe2 /Cr2 Se3 @N-HCSs heterojunction interface, dependent on the surface electron density of the antiferromagnetic Cr2 Se3 and the surface spin polarization near the Fermi level. After regulating the electron spin states through Mo-doping, the band gap of the material decreases. These significant findings provide novel insights into the design and synthesis of electrode materials with exceptional performance characteristics for batteries.

Facile synthesis of morphology-controlled hybrid structure of ZnCo2O4 nanosheets and nanowires for high-performance asymmetric supercapacitors.

Controllable synthesis of electrode materials with desirable morphology and size is of significant importance and challenging for high-performance supercapacitors. Herein, we propose an efficient hydrothermal approach to controllable synthesis of hierarchical porous three-dimensional (3D) ZnCo2O4 composite films directly on Ni foam substrates. The composite films consisted of two-dimensional (2D) nanosheets array anchored with one-dimensional (1D) nanowires. The morphologies of ZnCo2O4 arrays can be easily controlled by adjusting the concentration of NH4F. The effect of NH4F in the formation of these 3D hierarchical porous ZnCo2O4 nanosheets@nanowires films is systematically investigated based on the NH4F-independent experiments. This unique 3D hierarchical structure can help enlarge the electroactive surface area, accelerate the ion and electron transfer, and accommodate structural strain. The as-prepared hierarchical porous ZnCo2O4 nanosheets@nanowires films exhibited inspiring electrochemical performance with high specific capacitance of 1289.6 and 743.2 F g-1 at the current density of 1 and 30 A g-1, respectively, and a remarkable long cycle stability with 86.8% capacity retention after 10 000 cycles at the current density of 1 A g-1. Furthermore, the assembled asymmetric supercapacitor using the as-prepared ZnCo2O4 nanosheets@nanowires films as the positive electrode and active carbon as negative electrode delivered a high energy density of 39.7 W h kg-1 at a power density of 400 W kg-1. Our results show that these unique hierarchical porous 3D ZnCo2O4 nanosheets@nanowires films are promising candidates as high-performance electrodes for energy storage applications.

Tailoring electrochemical and dielectric properties of SrO nanostructures through Cr-doping for energy storage applications

Supercapacitors emerge as a revolutionary technology with the potential to transform future energy storage. Alkaline-earth metals are proposed as a promising option for high-performance supercapacitors due to their excellent redox characteristics and high energy density. However, their poor conductivity restricts applications. A propitious strategy involves incorporating transition metals to amplify alkaline-earth metal-based supercapacitor performance. In this study, we synthesize Cr-doped SrO nanostructures using the hydrothermal method. Structural analyses via X-ray diffraction and scanning electron microscopy unveil the cubic arrangement and rod-like morphology, respectively. Energy-dispersive X-ray spectroscopy corroborates the presence of essential elements: Sr, Cr, and O. Remarkably, UV-Vis measurements demonstrate a progressive reduction in energy bandgap (from 6.24 eV to 5.67 eV) with increasing Cr content. Photoluminescence spectra accentuate excitation at 300 nm, encompassing a broad emission band spanning 350 to 540 nm. With the infusion of Cr through doping, both ac (σac) conductivity and dielectric constant exhibit marked augmentation, concomitantly reducing dielectric loss. Impressively, the optimized 10% Cr-doped SrO electrode manifests a maximum specific capacitance (Csp) of 806 F/g at 1 A/g, accompanied by a specific energy of 28 Wh/kg and a remarkable specific power of 250 W/kg. Even after 3000 cycles, the optimized electrode exhibits an outstanding retention rate of 84%. Consequently, synthesized electrode materials emerge as a preeminent choice for advanced energy storage devices.

In situ biosynthesized polyphosphate nanoparticles/reduced graphene oxide composite electrode for highly sensitive detection of heavy metal ions

The development of an effective sensing platform is critical for the electrochemical detection of heavy metal ions (HMIs) in water. In this study, we fabricated a newly designed sensor through the in situ assembly of reduced graphene oxide (rGO) and polyphosphate nanoparticles (polyP NPs) on a carbon cloth electrode via microorganism-mediated green biochemical processes. The characterization results revealed that the rGO produced via microbial reduction had a three-dimensional porous structure, serving as an exceptional scaffold for hosting polyP NPs, and the polyP NPs were evenly distributed on the rGO network. In terms of detecting HMIs, the numerous functional groups of polyP NPs play a major role in the coordination with the cations. This electrochemical sensor, based on polyP NPs/rGO, enabled the individual and simultaneous determination of lead ion (Pb2+) and copper ion (Cu2+) with detection limits of 1.6 nM and 0.9 nM, respectively. Additionally, the electrode exhibited outstanding selectivity for the target analytes in the presence of multiple interfering metal ions. The fabricated sensor was successfully used to determine Pb2+/Cu2+ in water samples with satisfactory recovery rates ranging from 92.16% to 104.89%. This study establishes a facile, cost-effective, and environmentally friendly microbial approach for the synthesis of electrode materials and the detection of environmental pollutants.

Laser-Induced Electron Synchronization Excitation for Photochemical Synthesis and Patterning Graphene-Based Electrode.

Micro-supercapacitors (MSCs) represent a pressing requirement for powering the forthcoming generation of micro-electronic devices. The simultaneous realization of high-efficiency synthesis of electrode materials and precision patterning for MSCs in a single step presents an ardent need, yet it poses a formidable challenge. Herein, a unique shaped laser-induced patterned electron synchronization excitation strategy has been put forward to photochemical synthesis RuO2 /reduced graphene oxide (rGO) electrode and simultaneously manufacture the micron-scale high-performance MSCs with ultra-high resolution. Significantly, the technique represents a noteworthy advancement over traditional laser direct writing (LDW) patterning and photoinduced synthetic electrode methods. It not only improves the processing efficiency for MSCs and the controllability of laser-induced electrode material but also enhances electric fields and potentials at the interface for better electrochemical performance. The resultant MSCs exhibit excellent area and volumetric capacitance (516mFcm-2 and 1720Fcm-3 ), and ultrahigh energy density (0.41Whcm-3 ) and well-cycle stability (retaining 95% capacitance after 12000 cycles). This investigation establishes a novel avenue for electrode design and underscores substantial potential in the fabrication of diverse microelectronic devices.

Sonochemical synthesis of battery-type ZnCo2O4 electrode material with huge specific surface area for advanced hybrid supercapacitors

Sonochemistry is a novel and efficient method for the synthesis of electrode materials within micro-/nano-scale. In this work, the ZnCo2O4 nanoparticles (NPs) and chain-like ZnCo2O4 nanostructures, namely ZnCo2O4–7.5 and ZnCo2O4–9.5, were sonochemically prepared by controlling the pH value of reaction system combined with an extra calcination. The ZnCo2O4–7.5 NPs exhibited a larger specific surface area (SSA) of 148.77 m2 g−1, and presented better electrochemical properties such as a high specific capacity (Cs) of 331.2C g−1 under 2 A g−1 along with 82.5 % rate performance at 10 A g−1. As for the ZnCo2O4–9.5 nanostructure, it delivered an inferior Cs of 274.8C g−1 and showed a moderate rate capability with 75.6 % capacity retention, accordingly. The hybrid supercapacitor (HSC) device was assembled using such ZnCo2O4–7.5 NPs (ZnCo2O4–9.5 nanostructure) as cathode and activated carbon (AC) as anode to explore the application potential in the field of electrochemical energy storage. After 7000 cycles at the current density of 8 A g−1, both ZnCo2O4–7.5//AC and ZnCo2O4–9.5//AC HSCs showed outstanding cyclic stabilities with 100.4 % and 105.1 % of initial capacity retention, respectively. Meanwhile, the ZnCo2O4–7.5//AC HSC delivered a high energy density (Ed) of 38.1 W h kg−1 at the power density (Pd) of 1002.0 W kg−1, and it could still hold 26.3 W h kg−1 at the higher Pd of 9136.5 W kg−1. In contrast, the ZnCo2O4–9.5//AC HSC presented a slightly inferior Ed of 36.8 W h kg−1 at 1104.7 W kg−1. The both types of ZnCo2O4–7.5 and ZnCo2O4–9.5 electrode materials demonstrate excellent electrochemical property, and they can be expected to show brilliant application potential in the field of electrochemical energy storage & conversion when served as electrode materials for high-performance hybrid supercapacitors.

Enhanced supercapacitor performance through surface modification: Binder-free electrode synthesis of Ni3S2/MoS2/rGO on Ni-foam with superior cyclability

Tuning of microstructure and composition of the material is highly desirable for enhancing the specific capacity, rate capability and cycle stability of supercapacitor electrode materials. Herein direct growth of surface modified hierarchical Ni3S2/MoS2/rGO hybrid nanomaterial on Ni foam was successfully carried out by a one-step hydrothermal technique. Furthermore, the structural, morphological, elemental composition and electrochemical properties of as synthesized electrode material were analysed. The as synthesized Ni3S2/MoS2/rGO composite electrode delivered a very high specific capacity of 2580 F/g @ 1 A/g and excellent cycling stability with 100 % capacitance retention for 10,000 charge-discharge cycles with specific capacitance of 600 F/g @ current density 20 A/g. In addition, the assembled two electrode symmetric system showed high specific capacity 100.26 F/g @1 A/g and superior energy density of 112.79 Wh/kg with corresponding power density of 2699.82 W/kg @ 1 A/g. The results proved that the Ni3S2/MoS2/rGO directly grown on Ni foam without the addition of any external nickel source and binding polymer is an ideal candidate for supercapacitor applications.

Carbon Nitride Coupled Co3O4: A Pyrolysis-Based Approach for High-Performance Hybrid Energy Storage.

Graphitic carbon nitride (CN) is a cost-effective and easily synthesized supercapacitor electrode material. However, its limited specific capacity has hindered its practical use. To address this, we developed a binary nanostructure by growing nanosized Co3O4 particles on CN. The CN-Co-2 composite, synthesized via thermal decomposition, exhibited a remarkable specific capacity of 280.64 C/g at 2 A/g. Even under prolonged cycling at 10.5 A/g, the retention rate exceeded 95%, demonstrating exceptional stability. In an asymmetric capacitor device, the CN-Co composite delivered 20.84 Wh/kg at 1000 W/kg, with a retention rate of 99.97% over 20,000 cycles, showcasing outstanding cycling stability. Controlled cobalt source adjustments yielded high-capacity electrode materials with battery-like behavior. This optimization strategy enhances energy density by retaining battery-like properties. In summary, the CN-Co composite is a promising, low-cost, easily synthesized electrode material with a high specific capacity and remarkable cycling stability, making it an attractive choice for energy storage applications.

Constructing Interconnected Microporous Structures in Carbon by Homogeneous Activation as a Sustainable Electrode Material for High-Performance Supercapacitors.

Microporous carbon attracts attention as an electrode material for supercapacitors. However, a large number of deep and distorted mesoporous and macroporous structures are usually created by non-uniform etching, resulting in underutilized internal space. Homogeneous activation has been considered by researchers as a necessary condition for the formation of interconnected microporous structures in carbon materials. Herein, a simple strategy of hydrothermal introduction of defects followed by homogeneous activation for the preparation of microporous carbon was developed for the synthesis of electrode materials for high-performance supercapacitors. The optimized sample with defect-enriched microporous structure and large specific surface area has a specific capacity of 315 F g-1 (1 A g-1) in KOH solution, and the assembled symmetric supercapacitor achieves a high energy density of 7.3 Wh kg-1 at a power density of 250 W kg-1. This work is interesting because it not only demonstrates that rational design of electrode materials is important to boost the performance of supercapacitors, but also provides inspiration for the design of efficient supercapacitors in the future.

Supercapacitor performance of MOF-derived double-shell hollow Ni-Fe-Mn-Se nanocubes

In this study, Ni-Fe-Mn-Se nano boxes with a double-layer hollow structure were synthesized by a static self-assembly and hydrothermal method. To generate a stable structure, NiFe Prussian blue analogue (NiFe-PBA) was used as the substrate material. Moreover, a layer of polydopamine (PDA) was applied onto the surface of the PBA as a “connecting link” to protect the PBA core from collapsing internally and anchor metal ions, enabling the external in-situ growth of NiMn-LDH. A comparison was made between the morphology and properties of nano boxes that were etched using varying concentrations of selenium acid. It was observed that the combination of multi-metallic elements with Se effectively modified the electronic structure of the material, improving its electrical conductivity. The synthesized electrode material, Ni-Fe-Mn-Se, exhibited a high specific capacitance of 1433 F g−1 at 1 A g−1. Moreover, an asymmetric supercapacitor made of a Ni-Fe-Mn-Se cathode, Ni-Fe-Mn-Se//AC, demonstrated outstanding cycling stability (85 % capacitance retention after 8000 cycles) and a maximum energy density of 66.8 Wh kg−1 at a power density of 791 W kg−1. Thus, the electrode material synthesized in this study, Ni-Fe-Mn-Se, exhibits great promise for use in energy storage applications.

An impact of sea sponge-derived hard carbon with the symbiosis of sodium ion battery and biomedical applications

BackgroundSodium is pervasive and enormous compared to that of lithium. SIBs have turned out to be factual competitors to LIBs besides storage purposes, the power battery technology intended for electric vehicle transport. The choice of selecting SIBs is effective due to their alluring properties of biomaterials for synthesizing electrode materials. Hard carbon, (HC) owing to its amorphous and highly porous nature of the material leads to the intercalation/deintercalation of sodium ions. MethodsIn this work, the sea sponge (SS) was carbonized by the chemical-activating pyrolysis method. The as-prepared HCs using different chemical activating agents (KOH, NaOH, ZnCl2) reveals the diversified sodium-ion storage behaviors. Significant findingsSS attained a charge capacity of 347.39 mAh g−1 at a 0.1 C rate. The half maximal (IC50) of sea sponge-derived hard carbon was found to be 11.5, 11.4, 10.7 μg/mL against breast cancer cells (MDA MB - 231). The present work communally addressed the potential anode material and effective cancerous activity of sea sponge-derived hard carbon material.

Ionic liquids-assisted electrolytes in aqueous zinc ion batteries

In the quest for safer and low-cost batteries, zinc ion batteries have remarkable potential in various energy storage applications. However, selecting suitable electrolytes for zinc electrochemistry is challenging due to zinc's passivation and dendritic growth hindering long-term stability. Moreover, the synergy between newly developed electrode materials and electrolytes remains challenging for commercial applications. Therefore, in this study fifty (50) combinations of ionic liquids (ILs) were screened using COSMO-RS simulation to identify suitable ILs for aqueous electrolytes with ZnSO4 salt by comparing activity coefficients at infinite dilution, selectivity, and capacity of ILs to dissolve ZnSO4 salt in the aqueous phase. Further, calcium vanadate (CaV2O6) was synthesized using a modified molten salt method and characterized using a Scanning Electron Microscope and X-ray diffraction to confirm its successful synthesis. Afterwards, the performance of calcium vanadate in aqueous zinc batteries having ILs-assisted electrolytes were also evaluated and compared with conventional electrolyte (aqueous 1 M ZnSO4). Results revealed that ILs based on tetramethyl ammonium cation were suitable for electrolyte applications with ZnSO4 salt. Furthermore, Tetramethylammonium hydrogen sulfate was compared with conventional ZnSO4 electrolyte and an initial discharge capacity of 330 mAh/g for calcium vanadate electrode with ILs-assisted electrolyte was observed as compared to 230 mAh/g with 1 M ZnSO4 aqueous electrolyte. Electrochemical impedance spectroscopy (EIS) measurements showed that ILs-assisted electrolyte's charge transfer and surface film resistance were lower than the conventional electrolyte. However, additional advancement in electrode and electrolytes, i.e. synthesis of electrode materials, and formulation of ILs-assisted electrolytes, may further improve the performance of aqueous zinc ion batteries.

Symmetric supercapacitor comprising Ni2O3: Fe1.7Ni1.43O4 electrodes prepared by ultrasound chemical bath deposition route

Application of ultrasonic frequencies for synthesis of electrode materials is beneficial for the proper nucleation and growth of electrode material on substrates. Ni2O3:Fe1.7Ni1.43O4 electrodes (N100) were prepared by novel ultrasonic chemical bath deposition (UCBD). The formation of material was confirmed by XRD and further corroborated by EDX analysis. Hydrophilic nature was affirmed by contact angle of 15°. FESEM exhibits formation of interconnected nanograins of various sizes. Average grain size and average surface roughness were was 90 nm and 100 nm confirms the formation of a monolithic layer. The prepared symmetric supercapacitor shows maximum specific capacitance of 202.00 Fg−1 with almost 83% retention even after 2000 cycles.

Study on synthesis and characterization of electrocatalyst containing platinum on graphite electrode for hydrogen evolution reaction

In this study, we have successfully synthesized electrode materials containing Pt on modified graphite by electrodeposition method, such as: Pt/C, Pt-Au/C Pt-Pd/C, Pt-Ni/C, Pt-Ni-Au/C, Pt-Ni-Pd/C. The formation of materials coating on the modified graphite surface is demonstrated through SEM, EDS results. Synthetic materials are used as catalysts for hydrogen evolution reaction (HER). The results show that Bimetallic composites containing Pt exhibit higher catalytic activity than the monometallic material Pt/C. Trimetallic materials Pt-Ni-Au/C and Pt-Ni-Pd/C have catalytic activity for HER insignificant lower than that of Pt-Au/C and Pt-Pd/C electrodes. However, the precious metal composition in the trimetallic composite material system is reduced, which is also an important goal of research and opens up prospects for the fabrication of next-generation composite materials systems.

Facile synthesis strategy for phthalocyanine-titanium dioxide/multi-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) ternary composite electrodes via one-step electrochemical method for supercapacitor applications

Recent advances in the construction of ternary composite electrodes have revealed new strategies for energy storage applications. For energy storage applications, supercapacitors have attracted significant attention owing to their fascinating electrochemical performance and combining advantages. In this study, a facile and one-step electrochemical method was used for synthesis of metallo phthalocyanine-titanium dioxide/functionalized-multiwalled carbon nanotube/poly(3,4-ethylenedioxythiophene) ternary composite on pencil graphite electrode (MPc-TiO2/f-MWCNT/PEDOT/PGE) with high specific capacitance and long cycle life for supercapacitors. In this context, ZnPc-TiO2/f-MWCNT/PEDOT/PGE and NiPc-TiO2/f-MWCNT/PEDOT/PGE materials were produced by cyclic voltammetry method for the first time in the literature. The results of this study have revealed that multiwalled carbon nanotube/poly(3,4-ethylenedioxythiophene) when functionalized with metallo phthalocyanine-titanium dioxide shows higher specific capacitance than multiwalled carbon nanotube/poly(3,4-ethylenedioxythiophene) forms. Among the modified electrodes containing ternary composite, ZnPc-TiO2/f-MWCNT/PEDOT/PGE electrode showed highest specific capacitance (395.98 F.g−1) value. Additionally, both ZnPc-TiO2/f-MWCNT/PEDOT/PGE and NiPc-TiO2/f-MWCNT/PEDOT/PGE have long-cycle life and have highly maintained their capacitance after 1000 charge/discharge cycles. The developed simple and efficient strategy in this work is the first report on the electrochemical synthesis of MPc-TiO2/f-MWCNT/PEDOT, which opens up new perspective for synthesizing electrode materials for energy storage applications.

Symmetrical Composite Supercapacitor Based on Activated Carbon and Cobalt Nanoparticles with High Cyclic Stability and Current Load

Supercapacitors play an important role in a future clean-energy landscape to meet the challenges of existing energy-storage/delivery systems. They suffer from low energy density and are mainly used for the storage/delivery of electrical energy in high power demands. However, improvement of their energy density is vital to develop energy storage systems that can respond to the energy demands of emerging technologies requiring a wider energy/power spectrum. In this article, a symmetrical capacitor is developed from a composite consisting of synthesized activated carbon and cobalt oxide to improve the energy storage performance of the supercapacitor. Uniform distribution and immobilization of cobalt nanoparticles within the composite is achieved by embedding cobalt acetate into the initial resorcinol formaldehyde polymeric aerogels, followed by the pyrolysis of the gel in Ar atmosphere and activation of the carbon in CO2 atmosphere at 800 °C. The activated carbon/cobalt composite is used as the electroactive material in electrode formulation. The electrochemical characteristics of the synthesized electrode materials demonstrates an optimized specific capacitance of 235 F g−1 at a sweep rate of 10 mV s−1 in a three-electrode system. The symmetrical capacitor has a capacitance of 66 F g−1 at 1 A g−1, a very high rate of performance in 10,000 cycle tests, and a rate capability of 24% at 30 A g−1. The capacitor shows a power density of up to 15 Wh k g−1. The presence of cobalt spices makes it possible to optimize the capacitance of a symmetrical capacitor, while the capacitance of a symmetrical activated carbon capacitor cannot be optimized.