Composite Electrode Materials Research Articles

Cobalt ferrite (CoFe2O4)–activated carbon fabric (ACF) based composite electrode material for supercapacitor application

In the present article, rayon based activated carbon fiber/fabric (ACF) has been developed and explored as an active electrode material in combination with metal oxide for ultracapacitor application. Herein, the ACF is derived from rayon-based carbon fabric through activation and carbonization processes in a tubular furnace and prepared composite material of cobalt ferrite (CoFe2O4, Cof) and activated carbon fabric/fiber. The ACF, cobalt ferrite, and electrode material derived thereof are analyzed by FTIR, XPS, BET surface area analyzer, and XRD methods. The surface morphology and composition of prepared composite is examined by FESEM and EDX. The electrochemical properties of Cof-ACF composite are scrutinized by cyclic voltammetry. The composite material produces considerably high electrochemical supercapacitances in the order of 1287 F/g and 788 F/g at a potential sweep rate of 2 mV/s in 0.5 M phosphoric acid and 0.5 M sulphuric acid electrolytes, respectively. The electrochemical behavior of the cobalt ferrite decorated ACF electrode material exhibits a slightly higher energy density (176.98 Wh/kg) in H3PO4 than in H2SO4 (150.79 Wh/kg) electrolyte. The stability (~74 %) of electrode materials is retained even after 3500 cycles of charge/discharge in acid electrolytes. Thus, Cof-ACF composite material could be used as a cost-effective, compact, and light-weight electrode material with enhanced stability and improved performance for ultracapacitor and energy storage device applications in acid electrolytes.

Microwave-assisted synthesis of electrode materials for LIBs: MoS2/rGO heterostructures

The incomplete reduction of graphene oxide (GO) yields reduced graphene oxide (rGO), characterized by a zero band gap and intrinsic layer stacking, thus constraining its practical utility across diverse domains. Fortunately, this challenge can be effectively addressed by employing a suitable substrate for the fabrication of MoS2/rGO heterostructures. Nanocomposites of MoS2/reduced graphene oxide (MoS2/rGO-700W and MoS2/rGO-560W) were synthesized using MoS2 and GO solutions as starting materials through microwave-assisted synthesis with microwave power treatments of 700W and 560W, respectively. Structural characterization results reveal that the particle size of MoS2 within the composites is notably smaller compared to that of pure MoS2. The MoS2/rGO-700W composite demonstrates a more homogeneous dispersion of MoS2 and features a well-developed hierarchical porous structure with increased pore volume and specific surface area. The MoS2/rGO-700W composite demonstrates elevated ID/IG ratio, C/O ratio and C = C peak area, suggesting that increased microwave power enhances the removal of oxygen-containing groups from rGO. This process significantly restores the extended conjugated structure of graphene, thereby offering enhanced conductivity at the MoS2 interface. Furthermore, the proposed strategy holds considerable theoretical value and provides significant insights for the development process of novel MoS2-based composite electrode materials.

Electrode life evaluation for varied electrode material composition and geometry in resistance spot welding of aluminum alloys

Electrode life evaluation for varied electrode material composition and geometry in resistance spot welding of aluminum alloys

The Effect of TiO2 on the Electrochemical Performance of Sb2O3 Anodes for Li-Ion Batteries

Antimony (Sb) and its composites have been recognized as potentially good anode materials for lithium-ion batteries (LIBs) due to their relatively high theoretical capacity of 660 mAh g−1 and to their low cost. However, Sb-based anodes suffer from a high-volume change during the lithiation/delithiation process that results in capacity fading and anode degradation after prolonged charge/discharge cycles. To address this issue, Sb2O3/TiO2 nanocomposite electrodes can be synthesized and used as anodes for LIBs with high capacity and good electrochemical stability. In the present work, TiO2@Sb2O3 composites with different (TiO2:Sb2O3) ratios of 0:1, 1:1, 1:4 and 3:1 were synthesized and directly used as anode materials for LIBs. The electrochemical performance of the TiO2/Sb2O3 composite anode with different ratios of TiO2 to Sb2O3 was evaluated by galvanostatic charge/discharge, rate performance and cyclic voltammetry. The 3:1 (TiO2:Sb2O3) composite anode delivered the highest capacity compared to those of the TiO2, SbO3, 1:1 (TiO2:Sb2O3) and 1:4 (TiO2:Sb2O3) electrodes. The TiO2@Sb2O3 composite anode with a 3:1 ratio exhibited a stabilized capacity of 536 mAh g−1 after 100 cycles at 100 mA g−1 and showed excellent rate performance, with current densities between 50 and 500 mA g−1. The improved electrochemical performance was attributed to the synergistic effect of TiO2 (i.e., the coating of Sb2O3 with TiO2) on reducing the volume change of the Sb anode material after prolonged charge/discharge cycles and on maintaining a stable interface between the electrolyte and the composite electrode material.

High-performance flexible asymmetric supercapacitor utilizing hierarchical NiCo2O4 nanosheets supported on porous carbonized Verbena leaves

This study employed three-dimensional porous carbon with high surface area as the conductive substrate for composite electrode materials, aiming to facilitate rapid charge transfer and ion diffusion to increase the specific capacitance of pseudo-capacitive materials. We employed an in-situ hydrothermal method to anchor NiCo2O4 onto the porous carbonized verbena leaves, yielding nanostructured VC@NiCo2O4-8 composite electrode materials. At a current density of 1.0 A g-1, VC@NiCo2O4-8 exhibited a high specific capacitance of up to 2061.8 F g−1 and remarkable cycling stability (with only 7.8 % capacitance loss after 10000 cycles). Additionally, we assembled VC@NiCo2O4-8//VC asymmetric all-solid-state flexible supercapacitors, attaining a significant energy density of 54.0 Wh kg−1 at a power density of 695 W kg−1, while maintaining good flexibility and stability. This study provides a simple and effective method for the design and construction of high-performance electrode materials for flexible energy storage devices.

Facile synthesis of samarium (Sm3+) doped cobalt-iron oxide nano ferrite as an advanced electrode material for possible supercapacitor applications

Herein, we present design and fabrication of Samarium (Sm3+) doped cobalt-iron oxide ferrites nanocomposite electrode as an efficient energy storage material for supercapacitors. We employed a simple, low cost and quick one step solution combustion method to synthesize CoFe2-xSmxO4 (x = 0.0, 0.050, 0.075 and 0.1) ferrites. The morphological and structural features of synthesized CoFe2-xSmxO4 ferrites were analysed through various analytical and spectroscopic characterization methods such as scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). These analytical techniques confirm the successful doping of Samarium (Sm3+) into cobalt-iron ferrite, and the doping does not affect the crystalline structure of pure ferrite. The electrochemical properties of the synthesized ferrites were significantly improved after Samarium (Sm3+) doping into the host cobalt-iron-oxide. The highest specific capacity about 314 F/g was achieved for CoFe2-xSmxO4 (x = 0.1) composite electrode material, in comparison to pure CoFe2-xSmxO4 (x = 0) which is about 125 F/g. However, CoFe2-xSmxO4 (x = 0.1) ferrite shows a superior capacitance retention of the order of 98 % even after 5000 cycles of operation at a scan rate of 250 mV/s. The electrode material fabricated by using CoFe2-xSmxO4 ferrite renders an energy density of 30.16 W h/kg at a power density of 400 W h/kg. The results obtained in presented studies opens new avenues for the fabrication high-performance electrode material for supercapacitor that could be well suited for light weight electronic devices, electric vehicles, and forthcoming generation supercapacitor applications.

Architecting MxNy-MOF@MXene composites for excellent supercapacitor electrodes

The increasing demand for efficient energy storage systems has prompted the exploration of novel electrode materials, such as bimetallic metal-organic frameworks (MOFs). This study examines the synthesis of a variety of bimetallic MxNy-MOF materials, including Ni1Co1-MOF, Ni1Co3-MOF, Ni3Co1-MOF, Cu1Co1-MOF, and Ni1Cu1-MOF, as well as their integration with MXene to produce MOF@MXene composite electrode materials for supercapacitors. These MxNy-MOF materials display distinct morphologies and uniform particle sizes. MXene serves as an effective substrate, enhancing the surface coverage with the MOF phase. In interactions with MXene, Co2+ and Cu2+ demonstrate stronger binding than Ni2+, which prefers binding with ligands. Electrochemical testing reveals that Ni and Co-based composites, particularly Ni1Co1-MOF@MXene, exhibit superior performance and achieving a high specific capacitance of 1493.6 F g−1 at 1 A g−1. These materials also show impressive rate performance and cycle stability, with a retention of 57.2 % after 5,000 cycles. An all-solid-state flexible supercapacitor using Ni1Co1-MOF@MXene demonstrates an energy density of 73.9 Wh·kg−1 at a power density of 750 W·kg−1, maintaining 81.8 % capacity and 97 % Coulombic efficiency after 10,000 cycles. The energy storage mechanism primarily involves Faradaic redox reactions of Co2+/Co3+ and Ni2+/Ni3+, coupled with OH- adsorption/desorption processes. This study not only elucidates the kinetic dynamics and storage mechanisms of these composite materials but also highlights their potential applications in advanced energy storage technologies.

Ti─O─C Bonding at 2D Heterointerfaces of 3D Composites for Fast Sodium Ion Storage at High Mass Loading Level.

3D composite electrodes have shown extraordinary promise as high mass loading electrode materials for sodium ion batteries (SIBs). However, they usually show poor rate performance due to the sluggish Na+ kinetics at the heterointerfaces of the composites. Here, a 3D MXene-reduced holey graphene oxide (MXene-RHGO) composite electrode with Ti─O─C bonding at 2D heterointerfaces of MXene and RHGO is developed. Density functional theory (DFT) calculations reveal the built-in electric fields (BIEFs) are enhanced by the formation of bridged interfacial Ti─O─C bonding, that lead to not only faster diffusion of Na+ at the heterointerfaces but also faster adsorption and migration of Na+ on the MXene surfaces. As a result, the 3D composite electrodes show impressive properties for fast Na+ storage. Under high current density of 10mAcm-2, the 3D MXene-RHGO composite electrodes with high mass loading of 10mgcm-2 achieve a strikingly high and stable areal capacity of 3mAhcm-2, which is same as commercial LIBs and greatly exceeds that of most reported SIBs electrode materials. The work shows that rationally designed bonding at the heterointerfaces represents an effective strategy for promoting high mass loading 3D composites electrode materials forward toward practical SIBs applications.

Enhancement of energy density for iron MOF-derived composite for aqueous supercapacitor by K3[Fe(CN)6] redox additive electrolyte

Redox additive added aqueous electrolyte attract extensive interest in supercapacitor application. Herein, the electrochemical of the synthesized Fe3O4/Si/GNP composite cathode electrode material was conducted in a two-electrode system via Swagelok cell assembly in the presence of with and without redox additive (0.2 M K3Fe(CN)6 in 1 M Li2SO4). The Fe3O4/Si/GNP composite was successfully synthesized by facile solvothermal method followed by calcination. The structural and morphology investigations of the Fe3O4/Si/GNP composite are conducted via XRD, FESEM, and BET analyses. The synergic effects between the composite material and redox-active ion (Fe2+/Fe3+) in the redox additive electrolyte enhance faradaic reactions, which are utilized to design a high-energy density supercapacitor. The Fe3O4/Si/GNP composite in redox additive electrolyte exhibits a 64.38 % increase in specific capacitance (319.45 F g−1 at 1 A g−1) and a 70.95 % increase in terms of energy density (35.56 Wh kg−1). Redox additive ions in the electrolyte enhance ionic conductivity and facilitate electron transfer across the porous structure of the Fe3O4/Si/GNP composite. The fast reversible kinetics of iron ions enable it to sustain decent cycle stability with a capacitance retention of 73.7 % after 1200 cycles.

Graphene heterostructure fiber with enhanced physicochemical properties for flexible solid-state supercapacitors

The graphene/pseudocapacitive composite electrode materials used for energy storage usually benefit from the advantages of each component, however, they also face significant challenges in terms of structural integrity and rate performance due to the weak interactions and limited interface area between different phases. To tackle these issues, we propose a facile strategy that integrates 2D/2D van der Waals forces and hydrogen bonds to effectively and closely bind each component together. We illustrate this concept by designing and constructing a heterojunction fiber that immobilizes protonated g-C3N4 onto GO nanosheets through electrostatic self-assembly. The resulting g-C3N4/RGO heterostructure fiber exhibits enhanced electrical conductivity and improved mechanical properties. When utilized as a supercapacitor electrode, it demonstrates high specific capacitances of 70.6 F cm−3 at a current density (Id) value of 0.1 A cm−3, in addition to exceptional cyclic stability (Retaining 99.4 % after 15000 cycles), rate capability (Retaining 55.8 % at Id = 2 A cm−3), and enduring mechanical flexibility. We anticipate that this study will inspire the fabrication of heterostructure fibers for durable and high-rate energy storage devices.

High-performance supercapacitor electrode materials from composite of bamboo tar pitch activated carbon and tannic acid carbon quantum dots

A novel composite electrode material comprising bamboo tar pitch-based activated carbon (BTPAC) and tannic acid-derived carbon quantum dots (TACDs) was prepared. The integration of TACDs into the composite BTPAC-60/TACD not only preserved the high conductivity characteristic of BTPAC but also enhanced its hydrophilicity, pore structure, and specific surface area. Electrochemical evaluations revealed that BTPAC-60/TACD delivers a specific capacitance of 677.7 F/g at 0.5 A/g in a three-electrode system, and 281.8 F/g at 1 A/g in a two-electrode setup. Impressively, it achieves an energy density of 56.4 Wh/kg at a power density of 600 W/kg and maintains 95.7 % of its capacitance after 10,000 cycles. This research not only capitalizes on the high-value application of bamboo tar pitch but also provides a new perspective for the development of high-performance supercapacitor electrodes.

A novel composite electrode based on graphene oxide/MnO2:h‐MoO3 particles for square wave voltammetric determination of acetaminophen

AbstractA novel composite electrode was developed based on graphene oxide (GO)/MnO2:h‐MoO3 nanocomposite for sensitive and selective voltammetric detection of acetaminophen (ACP). The composite electrode materials were characterized using X‐Ray photoelectron spectroscopy (XPS), X‐Ray Diffraction (XRD), scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS) and cyclic voltammetric (CV) techniques. In the optimum conditions, the oxidation peak current (Ipa) of ACP was increased linearly with its concentration over two linear ranges from 0.06 to 10.0 μmol L−1 and 20.0 to 80.0 μmol L−1 with a detection limit of 0.0133 μmol L−1. Due to its higher selectivity and long term stability, the composite electrode was applied to the detection of ACP in pharmaceutical formulations.

Preparation and photoelectric properties of photoanode based on N-TiO2 deposited on copper electrode

Reducing the photoresistance of a photoanode is one of the key points to improving the electron transfer rate of dye-sensitive solar cells. With TiO2 sol acting as the titanium source and urea serving as the nitrogen source, the N-doped TiO2 composite electrode material was prepared by electrodeposition on the surface of copper foil. The results show that the N-TiO2/Cu electrode prepared by electrodeposition doping at a voltage of 1.0 V has a low photoresistance and bias of 0.25 V difference with the Cu electrode under visible light. The photocurrent is increased by 270 % in comparison with that of the TiO2/Cu electrode. The N-TiO2/Cu electrode shows good photoresponsivity and has a good potential application in dye-sensitive solar cells.

Molecular dynamic modeling and analysis of the sintering behaviors of GDC modified BSCF nanorods for rSOC oxygen electrode

Degradation including segregation and high stress related issues are significant challenges for reversible solid oxide cells (rSOCs), particularly concerning the oxygen electrode. Understanding the sintering preparation is crucial for enhancing the performance and reliability of the oxygen electrode under long-term dual-mode operation. In this study, the sintering process of Ba0.5Sr0.5Co0.8Fe0.2O3-δ nanorods anchored with Gd-doped CeO2 nanoparticles (GDC-BSCF-NR) was predicted by using molecular dynamics method. To optimize the sintering process, the stress distribution, A-site ion migration behavior and thermal properties of the composite electrode materials were analyzed at different sintering temperature, the effects of nanoparticle size were also investigated. Both thermal conductivity and thermal expansion increase with sintering temperature. The particle stress of the composites correlates positively with the diffusion coefficient of ions. The diffusion coefficients of surface and internal Ba/Sr ions increase by 6%–9% from 973 K to 1373 K, while stress increases by 19%–33 %. The diffusion coefficient of BSCF particles decrease by 15.1 % with an increase in GDC nanoparticle size, which is beneficial for suppressing Ba/Sr segregation.

Application of N/P-rGO composite electrode materials and novel electrolytes in high-performance supercapacitors

Traditional graphene-based electrode materials often can not have excellent gravimetric and volumetric electrochemical properties at the same time. Furthermore, the gel electrolyte widely used at present has the disadvantages of poor water retention, easy solidification, low ionic conductivity, and narrow working temperature range during the working process. In this paper, nanocellulose/N, P co-doped reduced graphene oxide composites (NC-NPrGOs) were synthesized via a simple approach using graphene oxide (GO), ammonium dihydrogen phosphate, and nanocellulose (NC) as raw materials. Meanwhile, a new type of gel electrolyte (SNG) with renewable, wide working temperature range and ultra-high water retention properties was prepared using sodium alginate (SA), NC, GO, and potassium hydroxide as precursors. Benefiting from the unique physical and chemical properties of NC-NPrGOs, the assembled aqueous symmetric supercapacitors assembled by NC-NPrGOs present high gravimetric (303.9 F/g) and volumetric specific capacitance (416.5 F cm−3), large gravimetric (10.5 Wh kg−1) and volumetric energy density (14.6 Wh/L). Due to the multiple interactions of several components in SNG, the flexible solid-state supercapacitors (ASSC) assembled by NC-NPrGO55 and SNG deliver high specific capacitance (240.0 F/g), ultra-long cycling life, excellent bending resistance, a wide range of operating temperatures, and good regenerative performance. In summary, NC-NPrGOs and SNGs are ideal for the investigation of new energy storage devices.

Facile synthesis of Zn2V2O7/RGO nanocomposite for enhancing the electrochemical performance and evaluating the supercapacitor device

Pyrochlore-structured zinc vanadium oxide with RGO (Zn2V2O7/RGO) composite was synthesized using the simple hydrothermal process for energy storage device fabrication. The structural, vibration spectrum, surface morphology, and elemental of the Zn2V2O7/RGO composite were analyzed using different analytical methods. Then, the electrochemical performance was examined using Zn2V2O7/RGO composite modified electrode with 3-electrode and 2-electrode setup by cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectrum (EIS) techniques. Consequently, the Zn2V2O7/RGO composite revealed notable pseudo-capacitive behavior which has been confirmed through CV analysis. The nano size-based Zn2V2O7/RGO composite electrode material obtained notable specific capacitance (Csp) of 1400.51F/g owing to the synergistic promotion of Zinc and vanadium oxides. Furthermore, the ASC device of Zn2V2O7/RGO ||RGO displayed the efficient power density of 1371 kW/kg at the energy density of 8Wh/kg and the device has enhanced cycling performance with 72.8 % capacitance.

Two {CuI[P4Mo6]2}-Based Coordination Polymers Incorporating In Situ Converted Tetrapyridyl Ligands for Trace Analysis of Nitrofuran Antibiotics.

Nitrofurans are important synthetic broad-spectrum antibacterial drugs with the basic structure of 5-nitrofuran. Due to their toxicity, it is essential to develop a sensitive sensor with strong anti-interference capabilities for their detection. In this work, two {P4Mo6O31}12--based compounds, [H4(HPTTP)]2{CuI[Mo12O24(OH)6(PO4)3(HPO4)(H2PO4)4]}·xH2O (x = 13 for (1), 7 for (2); HPTTP = 4,4',4″,4‴-(1H-pyrrole-2,3,4,5-tetrayl)tetrapyridine), exhibiting similar coordination but distinct stacking modes. Both compounds were synthesized and used for the electrochemical detection of nitrofuran antibiotics. The tetrapyridine-based ligand was generated in situ during assembly, and its potential mechanism was discussed. Composite electrode materials, formed by mixing graphite powder with compounds 1-2 and physically grinding them, proved to be highly effective in the electrochemical trace detection of furazolidone (FZD) and furaltadone hydrochloride (FTD·HCl) under optimal conditions. Besides, the possible electrochemical detection mechanisms of two nitro-antibiotics were studied.

Preparation of Positive and Negative Composite Electrode Materials for High-Performance Aqueous Asymmetric Supercapacitor by a Sequential Two-Step Reaction

Preparation of Positive and Negative Composite Electrode Materials for High-Performance Aqueous Asymmetric Supercapacitor by a Sequential Two-Step Reaction

Fabrication of metal-organic framework@cellulose nanofibers/reduced graphene oxide-Vitrimer composite electrode materials with shape memory for supercapacitors

With the rapid development of flexible electronic devices towards small, light, and high-performance, people's requirements for electrode materials that affect energy storage devices are also increasing. It is crucial to prepare composite electrode materials with excellent comprehensive performance through reasonable design. This study successfully prepared a novel Ni-metal-organic framework (Ni-MOF) @ cellulose nanofibers (CNF)/reduced graphene oxide (rGO) -Vitrimer (MOF@CNF/rGO-V) electrode material through freeze-drying and solvent-thermal methods. In the hybrid, CNF not only prevents the stacking of rGO but also serves as a flexible substrate for loading Ni-MOF, while the porous structure of the CNF aerogel provides numerous channels for electrolyte ions to store and transport. The presence of Ni-MOF loaded on the conductive substrate contributes to a high pseudo-capacitance, ultimately yielding a composite material with a high specific capacitance (189.9 F g−1). Furthermore, when the composite was assembled into a symmetric supercapacitor device, it exhibited an energy density of 35.61 W h kg−1 at a power density of 641.07 W kg−1 and a remarkable cycling stability of up to 96.59% after experiencing 20,000 cycles. In addition, the introduction of Vitrimer successfully prevented electrode material detachment or fracture during use while maintaining excellent electrochemical and mechanical properties, imparting shape-memory functionality. The as-fabricated MOF@CNF/rGO-V composite electrode material holds significant promise and attractiveness in the field of flexible wearable electronics.

Preparation ofa Fe2O3/Reduced Graphene Oxide/Carbon Nanotube Composite with Highly Dispersed Fe2O3Particles:Electrochemical Performance as an Anode of Lithium Ion Batteries

AbstractIn this paper, a series of iron oxide/reduced graphene oxide/carbon nanotube composites (K3‐Fe2O3‐rGO/CNT) with well‐dispersedFe2O3 particles are prepared by in situ reaction and then heat‐treatment, and its electrochemical and battery performancesare studied as the anode material of lithium‐ion batteries. The results show that the introduction of reduced graphene oxide/carbon nanotube (rGO/CNT) improves the electrochemical and battery performances of the prepared electrode material. In particular, the K3‐Fe2O3‐rGO/CNT (30 %) composite material has a reversible capacity of 1559 mAh g−1 after 100 charge/discharge cycles at 100 mA g−1. And its specific discharge capacityis 641.1, 639.7, 609.5, 578.6 and 543 mAh g−1at the current density of 100, 200, 500, 1000 and 2000 mA g−1, respectively,with 84.7 % of capacity retention even with a 10 times increase in current density. The research of charge storage indicates that the electrochemical process is a mixed control process of diffusion and capacitance. The improved electrochemical and battery performancesfor the composite electrode material can be attributed to the enhanced dispersion of the Fe2O3 and the enhanced conductive network provided by rGO/CNT composite carbon. It makes a promising way to prepare high performance of anode material for lithium‐ion battery.